Clustering SAP #ASCS and #ERS on #AWS using Windows Server Failover Clustering

When ensuring high availability for SAP ASCS and ERS running on WIndows Server, the primary cluster solution you will want to use is Windows Server Failover Clustering. However, when doing this in AWS you will quickly discover that there are a few obstacles you need to know how to overcome when deploying this in AWS.

I recently wrote this Step-by-Step guide that was published on the SAP blog that walks you through the entire process. If you have any questions, please leave a comment.

Clustering SAP #ASCS and #ERS on #AWS using Windows Server Failover Clustering

How to create a DataKeeper Replicated Volume that has Multiple Targets via CLI

I often help people automate the configuration of their infrastructure so they can build 3-node clusters that span Availability Zones and Regions. The CLI for creating a DataKeeper Job and associated mirrors that contain more than one target can be a little confusing, so I’m documenting it here in case you find yourself looking for this information. The DataKeeper documentation describes this as a Mirror with Multiple Targets.

The environment in this example looks like this:

PRIMARY (10.0.2.100) – in AZ1
SECONDARY (10.0.3.100) – in AZ2
DR (10.0.1.10) – in a different Region

I want to create a synchronous mirror from PRIMARY to SECONDARY and an asynchronous mirror from PRIMARY to DR. I also have to make sure the DataKeeper Job knows how to create a mirror from SECONDARY to DR in case the SECONDARY or DR server ever become the source of the mirror. EMCMD will be used to create this multiple target mirror.

We need to first create the Job that contains all this possible endpoints and define whether the mirror will be Sync (S) or Async (A) between those endpoints.

emcmd . createjob ddrive sqldata primary.datakeeper.local D 10.0.2.100 secondary.datakeeper.local D 10.0.3.100 S primary.datakeeper.local D 10.0.2.100 dr.datakeeper.local D 10.0.1.10 A secondary.datakeeper.local D 10.0.3.100 dr.datakeeper.local D 10.0.1.10 A

That single “createjob” command creates the Job. It might be a little easier to look at that command like this:

emcmd . createjob ddrive sqldata 
primary.datakeeper.local D 10.0.2.100 secondary.datakeeper.local D 10.0.3.100 S 
primary.datakeeper.local D 10.0.2.100 dr.datakeeper.local D 10.0.1.10 A 
secondary.datakeeper.local D 10.0.3.100 dr.datakeeper.local D 10.0.1.10 A

Next we need to create the mirrors.

emcmd 10.0.2.100 createmirror D 10.0.1.10 A
emcmd 10.0.2.100 createmirror D 10.0.3.100 S

Our DataKeeper Job should now look like this in the DataKeeper UI

One-to-many DataKeeper Replicated Volume

And then finally we can register the DataKeeper Volume Resource in the cluster Available Storage with this command.

emcmd . registerclustervolume D

The DataKeeper Volume Resource will now appear in Available Storage as shown below.

DataKeeper Volume in Available Storage

You are now ready to install SQL Server, SAP, File Server or any other clustered resource you normally protect with Windows Server Failover Clustering.

How to create a DataKeeper Replicated Volume that has Multiple Targets via CLI

How to extend your existing SQL Server Failover Cluster Instance to the Cloud for Disaster Recovery

I get asked this question all the time, so I figured it was time to write a blog post, record a video and write some code to automate the process so that it completes in under a minute.

First, some background. Typically when someone asks me how to do this, I point them to the DataKeeper documentation.

https://docs.us.sios.com/WindowsSPS/8.2/DKLE/DKCloudTechDoc/Content/DataKeeper/User_Guide/Extending_a_Traditional_2-Node_WSFC_Cluster_to_a_Third_Node_via_DataKeeper.htm.

This first document talks about extending the cluster and adding a 3rd node to the existing cluster. That’s fine if your cluster supports three nodes, but if you are using SQL Server Standard Edition, Microsoft limits you to a 2-node cluster. In the case of a 2-node cluster you can still replicate to a 3rd node, but the recovery will be more of a manual process. This process is described here.

https://docs.us.sios.com/WindowsSPS/8.6/SPS4W/TechDoc/Content/DataKeeper/User_Guide/Extend_to_Non_Cluster_Node.htm

People typically read these instructions and get a little worried. They feel like they would be performing open heart surgery on their cluster. It really is more like changing your shirt! You are simply replacing the Cluster Disk resource with a DataKeeper Volume resource. As you’ll see in the video below the process takes just a few seconds.

The code demonstrated in the video is show below.

Stop-ClusterGroup SQLServerGroup
Remove-ClusterResource -Name "Cluster Disk 1"
Set-Disk -Number 4 -IsOffline $False
Set-Disk -Number 4 -IsReadOnly $False
Import-Module -Name Storage
Set-Partition -DiskNumber 4 -PartitionNumber 1 -NewDriveLetter X
New-DataKeeperMirror -SourceIP 10.0.2.100 -SourceVolume X -TargetIP 10.0.1.10 -TargetVolume X -SyncType Sync
New-DataKeeperJob -JobName "x drive" -JobDescription "sql data" -Node1Name primary.datakeeper.local -Node1IP 10.0.2.100 -Node1Volume x -Node2Name dr.datakeeper.local -Node2IP 10.0.1.10 -Node2Volume X -SyncType Sync
Add-ClusterResource -Name "DataKeeper Volume X" -ResourceType "DataKeeper Volume" -Group "SQLServerGroup"
Get-ClusterResource "DataKeeper Volume X" | Set-ClusterParameter VolumeLetter X
Get-ClusterResource -Name 'SQLServer' | Add-ClusterResourceDependency -Provider 'DataKeeper Volume X'
Start-ClusterGroup SQLServerGroup 

After you run that code don’t forget you also need to click on Manage Shared Volumes to add the backup node to the DataKeeper job as shown in the video.

If you have SQL Server Enterprise Edition then the final step would be to install SQL Server in the DR node and choose add node to existing cluster.

If you are using SQL Server Standard Edition then your job is done. You would simply follow these instructions to access you data on the 3rd node and then mount the replicated databases.

These directions are applicable whether your DR node is in the Cloud or your own DR site.

How to extend your existing SQL Server Failover Cluster Instance to the Cloud for Disaster Recovery

Using Amazon FSx for SQL Server Failover Cluster Instances – What You Need to Know!

Intro

If you are considering deploying your own Microsoft SQL Server instances in AWS EC2 you have some decisions to make regarding the resiliency of the solution. Sure, AWS will offer you a 99.99% SLA on your Compute resources if you deploy two or more instances across different availability zones. But don’t be fooled, there are a lot of other factors you need to consider when calculating your true application availability. I recently blogged about how to calculate your application availability in the cloud. You probably should have a quick read of that article before you move on.

When it comes to ensuring your Microsoft SQL Server instance is highly available, it really comes down to two basic choices: Always On Availability Group (AG) or SQL Server Failover Cluster Instance (FCI). If you are reading this article I’m making an assumption you are well aware of both of these options and are seriously considering using a SQL Server FCI instead of a SQL Server Always On AG.

Benefits of a Microsoft SQL Server Failover Cluster Instance

The following list summarize what AWS says are the benefits of a SQL Server FCI:

FCI is generally preferable over AG for SQL Server high availability deployments when the following are priority concerns for your use case:

License cost efficiency: You need the Enterprise Edition license of SQL Server to run AGs, whereas you only need the Standard Edition license to run FCIs. This is typically 50–60% less expensive than the Enterprise Edition. Although you can run a Basic version of AGs on Standard Edition starting from SQL Server 2016, it carries the limitation of supporting only one database per AG. This can become a challenge when dealing with applications that require multiple databases like SharePoint.

Instance-level protection versus database-level protection: With FCI, the entire instance is protected – if the primary node becomes unavailable, the entire instance is moved to the standby node. This takes care of the SQL Server logins, SQL Server Agent jobs, certificates, etc. that are stored in the system databases, which are physically stored in shared storage. With AG, on the other hand, only the databases in the group are protected, and system databases cannot be added to an AG – only user databases are allowed. It is the database administrator’s responsibility to replicate changes to system objects on all AG replicas. This leaves the possibility of human error causing the database to become inaccessible to the application.

DTC feature support: If you’re using SQL Server 2012 or 2014, and your application uses Distributed Transaction Coordinator (DTC), you are not able to use an AG as it is not supported. Use FCI in this situation.

https://aws.amazon.com/blogs/storage/simplify-your-microsoft-sql-server-high-availability-deployments-using-amazon-fsx-for-windows-file-server/

Challenges with FCI in the Cloud

Of course, the challenge with building an FCI that spans availability zones is the lack of a shared storage device that is normally required when building a SQL Server FCI. Because the nodes of the cluster are distributed across multiple datacenters, a traditional SAN is not a viable option for shared storage. That leaves us with a two choices for cluster storage: 3rd party storage class resources like SIOS DataKeeper or the new Amazon FSx. Let’s take a look at what you need to know before you make your choice.

Service Level Agreement

As I wrote in how to calculate your application availability, your overall application SLA is only as good as your weakest link. In this case, the FSx SLA of 99.9%.

Normally 99.99% availability represents the starting point of what is considered “highly available”. This is what AWS promises you for your compute resources when two or more are deployed in different availability zones.

In case you didn’t know the difference between three nines and four nines…

  • 99.9% availability allows for 43.83 minutes of downtime per month
  • 99.99% availability allows for only 4.38 minutes of downtime per month

By hosting your cluster storage on FSx despite your 99.99% compute availability, your overall application availability will be 99.9%. In contrast, EBS volumes that span availability zones, such as in a DataKeeper deployment, qualifies for the 99.99% SLA at both the storage and compute layers, meaning your overall application availability is 99.99%.

Storage Location

When configuring FSx for high availability, you will want to enable multi-AZ support. By enabling multi-AZ you have an effectively have a “preferred” AZ and a “standby” AZ. When you deploy your SQL Server FCI nodes you will want to distribute those nodes across the same AZs.

Now in normal situations, you will want to make sure the active cluster node resides in the same AZ as the preferred FSx storage node. This is to minimize the distance and latency to your storage, but also to minimize the costs associated with data transfer across AZs. As specified in the FSx price guide, “Standard data transfer fees apply for inter-AZ or inter-region access to file systems.”

In the unfortunate circumstance where you have a SQL Server FCI failure, but not a FSx failure, there is no mechanism to tie both the storage and compute together. In the event that FSx fails over, it will automatically fail back to the primary availability zone. However, best practices dictate SQL FCI remain running on the secondary node until root cause analysis is performed and fail back is typically scheduled to occur during maintenance periods. This leaves you in a situation where your storage resides in a different AZ, which will incur additional costs. Currently the cost for transferring data across AZs, both ingress and egress, is $0.01/GB.

Without keeping a close eye on the state of your FSx and SQL Server FCI, you may not even be aware that they are running in different regions until you see the data transfer charge at the end of the month.

In contrast, in a configuration that use SIOS DataKeeper, the storage failover is part of the SQL Server FCI recovery, ensuring that the storage always fails over with the SQL Server instance. This ensures SQL Server is always reading and writing to the EBS volumes that are directly attached to the active node. Keep in mind, DataKeeper will incur a data transfer cost associated with write operations which are replicated between AZs or regions. This data transfer cost can be minimized with the use of compression available in DataKeeper.

Controlling Failover

In an FSx multi-subnet configuration there is a preferred availability zone and a standby availability. Should the FSx file server in the preferred availability zone experience a failure, the file server in the standby AZ will recover. AWS reports that this recovery time takes about 30 seconds with standard shares. With the use of continuously available file shares Microsoft reports this failover time can be closer to 15 seconds. During this failover time, there is a brownout that occurs where reads and writes are paused, but will continue once recovery completes.

FSx multi-site has automatic failback enabled, meaning that for every unplanned failover of FSx, you also have an unplanned failback. In contrast, typically when a SQL Server FCI experience an unplanned failover you would either just leave it running on the secondary or schedule a failback after hours or during the next maintenance period.

SQL Server Analysis Services Cluster Not Supported with FSx

If you want to cluster SSAS, you will need a clustered disk resource like SIOS DataKeeper. The How to Cluster SQL Server Analysis Server white paper clearly states that SMB cannot be used and that cluster drives with drive letters must be used. In contrast, the DataKeeper Volume resource presents itself as a clustered disk and can be used with SSAS.

Summary

While FSx certainly can make sense for typical SMB uses like Windows user files and other non-critical services where 99.9% availability SLA suffices, FSx is an excellent option If you application requires high availability (99.99%) or HA/DR solutions that also span regions, the SIOS DataKeeper is the right fit.

Using Amazon FSx for SQL Server Failover Cluster Instances – What You Need to Know!

Step-by-Step: iSCSI Target Server Cluster in Azure

I recently helped someone build an iSCSI target server cluster in Azure and realized that I never wrote a step-by-step guide for that particular configuration. So to remedy that, here are the step-by-step instructions in case you need to do this yourself.

Pre-requisites

I’m going to assume you are fairly familiar with Azure and Windows Server, so I’m going to spare you some of the details. Let’s assume you have at least done the following as a pre-requisite

  • Provision two servers (SQL1, SQL2) each in a different Availability Zone (Availability Set is also possible, but Availability Zones have a better SLA)
  • Assign static IP addresses to them through the Azure portal
  • Joined the servers to an existing domain
  • Enabled the Failover Clustering feature and the iSCSI Target Server feature on both nodes
  • Add three Azure Premium Disk to each node.
    NOTE: this is optional, one disk is the minimum required. For increased IOPS we are going to stripe three Premium Azure Disks together in a storage pool and create a simple (RAID 0) virtual disk
  • SIOS DataKeeper is going to be used to provided the replicated storage used in the cluster. If you need DataKeeper you can request a trial here.

Create local Storage Pool

Once again, this step is completely optional, but for increased IOPS we are going to stripe together three Azure Premium Disks into a single Storage Pool. You might be tempted to use Dynamic Disk and a spanned volume instead, but don’t do that! If you use dynamic disks you will find out that there is some general incompatibility that will prevent you from creating iSCSI targets later.

Don’t worry, creating a local Storage Pool is pretty straight forward if you are aware of the pitfalls you might encounter as described below. The official documentation can be found here.

Pitfall #1 – although the documentation says the minimum size for a volume to be used in a storage pool is 4 GB, I found that the P1 Premium Disk (4GB) was NOT recognized. So in my lab I used 16GB P3 Premium Disks.

Pitfall #2 – you HAVE to have at least three disks to create a Storage Pool.

Pitfall #3 – create your Storage Pool before you create your cluster. If you try to do it after you create your cluster you are going to wind up with a big mess as Microsoft tries to create a clustered storage pool for you. We are NOT going to create a clustered storage pool, so avoid that mess by creating your Storage Pool before you create the cluster. If you have to add a Storage Pool after the cluster is created you will first have to evict the node from the cluster, then create the Storage Pool.

Based on the documentation found here, below are the screenshots that represent what you should see when you build your local Storage Pool on each of the two cluster nodes. Complete these steps on both servers BEFORE you build the cluster.

You should see the Primordial pool on both servers.
Right-click and choose New Storage Pool…
Choose Create a virtual disk when this wizard closes
Notice here you could create storage tiers if you decided to use a combination of Standard, Premium and Ultra SSD
For best performance use Simple storage layout (RAID 0). Don’t be concerned about reliability since Azure Managed Disks have triple redundancy on the backend. Simple is required for optimal performance.
For performance purposes use Fixed provisioning. You are already paying for the full Premium disk anyway, so no need not to use it all.
Now you will have a 45 GB X drive on your first node. Repeat this entire process for the second node.

Create your Cluster

Now that each server each have their own 45 GB X drive, we are going to create the basic cluster. Creating a cluster in Azure is best done via Powershell so that we can specify a static IP address. If you do it through the GUI you will soon realize that Azure assigns your cluster IP a duplicate IP address that you will have to clean up, so don’t do that!

Here is an example Powershell code to create a new cluster.

 New-Cluster -Name mycluster -NoStorage -StaticAddress 10.0.0.100 -Node sql1, sql2

The output will look something like this.

PS C:\Users\dave.DATAKEEPER> New-Cluster -Name mycluster -NoStorage -StaticAddress 10.0.0.100 -Node sql1, sql2
WARNING: There were issues while creating the clustered role that may prevent it from starting. For more information view the report file below.
WARNING: Report file location: C:\windows\cluster\Reports\Create Cluster Wizard mycluster on 2020.05.20 At 16.54.45.htm

Name     
----     
mycluster

The warning in the report will tell you that there is no witness. Because there is no shared storage in this cluster you will have to create either a Cloud Witness or a File Share Witness. I’m not going to walk you through that process as it is pretty well documented at those links.

Don’t put this off, go ahead and create the witness now before you move to the next step!

You now should have a basic 2-node cluster that looks something like this.

Configure a Load Balancer for the Cluster Core IP Address

Clusters in Azure are unique in that the Azure virtual network does not support gratuitous ARP. Don’t worry if you don’t know what that means, all you have to really know is that cluster IP addresses can’t be reached directly. Instead, you have to use an Azure Load Balancer, which redirects the client connection to the active cluster node.

There are two steps to getting a load balancer configured for a cluster in Azure. The first step is to create the load balancer. The second step is to update the cluster IP address so that it listens for the load balancer’s health probe and uses a 255.255.255.255 subnet mask which enables you to avoid IP address conflicts with the ILB.

We will first create a load balancer for the cluster core IP address. Later we will edit the load balancer to also address the iSCSI cluster resource IP address that we will be created at the end of this document.

Step 1 – Create a Standard Load Balancer

Notice that the static IP address we are using is the same address that we used to create the core cluster IP resource.

Once the load balancer is created you will edit the load balancer as shown below

Add the two cluster nodes to the backend pool
Add a health probe. In this example we use 59999 as the port. Remember that port, we will need it in the next step.
Create a new rue to redirect all HA ports, Make sure Floating IP is enabled.

Step 2 – Edit to cluster core IP address to work with the load balancer

As I mentioned earlier, there are two steps to getting the load balancer configured to work properly. Now that we have a load balancer, we have to run a Powershell script on one of the cluster nodes. The following is an example script that needs to be run on one of the cluster nodes.

$ClusterNetworkName = “Cluster Network 1” 
$IPResourceName = “Cluster IP Address” 
$ILBIP = “10.0.0.100” 
Import-Module FailoverClusters
Get-ClusterResource $IPResourceName | Set-ClusterParameter -Multiple @{Address=$ILBIP;ProbePort=59998;SubnetMask="255.255.255.255";Network=$ClusterNetworkName;EnableDhcp=0} 

The important thing about the script above, besides getting all the variables correct for your environment, is making sure the ProbePort is set to the same port you defined in your load balancer settings for this particular IP address. You will see later that we will create a 2nd health probe for the iSCSI cluster IP resource that will use a different port. The other important thing is making sure you leave the subnet set at 255.255.255.255. It may look wrong, but that is what it needs to be set to.

After you run it the output should look like this.

 PS C:\Users\dave.DATAKEEPER> $ClusterNetworkName = “Cluster Network 1” 
$IPResourceName = “Cluster IP Address” 
$ILBIP = “10.0.0.100” 
Import-Module FailoverClusters
Get-ClusterResource $IPResourceName | Set-ClusterParameter -Multiple @{Address=$ILBIP;ProbePort=59999;SubnetMask="255.255.255.255";Network=$ClusterNetworkName;EnableDhcp=0}
WARNING: The properties were stored, but not all changes will take effect until Cluster IP Address is taken offline and then online again.

You will need to take the core cluster IP resource offline and bring it back online again before it will function properly with the load balancer.

Assuming you did everything right in creating your load balancer, your Server Manager on both servers should list your cluster as Online as shown below.

Check Server Manager on both cluster nodes. Your cluster should show as “Online” under Manageability.

Install DataKeeper

I won’t go through all the steps here, but basically at this point you are ready to install SIOS DataKeeper on both cluster nodes. It’s a pretty simple setup, just run the setup and choose all the defaults. If you run into any problems with DataKeeper it is usually one of two things. The first issue is the service account. You need to make sure the account you are using to run the DataKeeper service is in the Local Administrators Group on each node.

The second issue is in regards to firewalls. Although the DataKeeper install will update the local Windows Firewall automatically, if your network is locked down you will need to make sure the cluster nodes can communicate with each other across the required DataKeeper ports. In addition, you need to make sure the ILB health probe can reach your servers.

Once DataKeeper is installed you are ready to create your first DataKeeper job. Complete the following steps for each volume you want to replicate using the DataKeeper interface

Use the DataKeeper interface to connect to both servers
Click on create new job and give it a name
Click Yes to register the DataKeeper volume in the cluster
Once the volume is registered it will appear in Available Storage in Failover CLuster Manager

Create the iSCSI target server cluster

In this next step we will create the iSCSI target server role in our cluster. In an ideal world I would have a Powershell script that does all this for you, but for sake of time for now I’m just going to show you how to do it through the GUI. If you happen to write the Powershell code please feel free to share with the rest of us!

There is one problem with the GUI method. ou will wind up with a duplicate IP address in when the IP Resource is created, which will cause your cluster resource to fail until we fix it. I’ll walk through that process as well.

Go to the Properties of the failed IP Address resource and choose Static IP and select an IP address that is not in use on your network. Remember this address, we will use it in our next step when we update the load balancer.

You should now be able to bring the iSCSI cluster resource online.

Update load balancer for iSCSI target server cluster resource

Like I mentioned earlier, clients can’t connect directly to the cluster IP address (10.0.0.110) we just created for the iSCSI target server cluster. We will have to update the load balancer we created earlier as shown below.

Start by adding a new frontend IP address that uses the same IP address that the iSCSI Target cluster IP resource uses.
Add a second health probe on a different port. Remember this port number, we will use it again in the powershell script we run next
We add one more load balancing rule. Make sure to change the Frontend IP address and Health probe to use the ones we just created. Also make sure direct server return is enabled.

The final step to allow the load balancer to work is to run the following Powershell script on one of the cluster nodes. Make sure you use the new Healthprobe port, IP address and IP Resource name.

 $ClusterNetworkName = “Cluster Network 1” 
$IPResourceName = “IP Address 10.0.0.0” 
$ILBIP = “10.0.0.110” 
Import-Module FailoverClusters
Get-ClusterResource $IPResourceName | Set-ClusterParameter -Multiple @{Address=$ILBIP;ProbePort=59998;SubnetMask="255.255.255.255";Network=$ClusterNetworkName;EnableDhcp=0} 

Your output should look like this.

 PS C:\Users\dave.DATAKEEPER> $ClusterNetworkName = “Cluster Network 1” 
$IPResourceName = “IP Address 10.0.0.0” 
$ILBIP = “10.0.0.110” 
Import-Module FailoverClusters
Get-ClusterResource $IPResourceName | Set-ClusterParameter -Multiple @{Address=$ILBIP;ProbePort=59998;SubnetMask="255.255.255.255";Network=$ClusterNetworkName;EnableDhcp=0}
WARNING: The properties were stored, but not all changes will take effect until IP Address 10.0.0.0 is taken offline and then online again.

Make sure to take the resource offline and online for the settings to take effect.

Create your clustered iSCSI targets

Before you begin, it is best to check to make sure Server Manager from BOTH servers can see the two cluster nodes, plus the two cluster name resources, and they both appear “Online” under manageability as shown below.

If either server has an issue querying either of those cluster names then the next steps will fail. If there is a problem I would double check all the steps you took to create the load balancer and the Powershell scripts you ran.

We are now ready to create our first clustered iSCSI targets. From either of the cluster nodes, follows the steps illustrated below as an example on how to create iSCSI targets.

Of course assign this to whichever server or servers will be connecting to this iSSI target.

And there you have it, you now have a functioning iSCSI target server in Azure.

If you build this leave a comment and me know how you plan to use it!

Step-by-Step: iSCSI Target Server Cluster in Azure

STEP-BY-STEP: HOW TO CONFIGURE A SQL SERVER 2008 R2 FAILOVER CLUSTER INSTANCE ON WINDOWS SERVER 2008 R2 IN AZURE OR AZURE STACK

Intro

On July 9, 2019, support for SQL Server 2008 and 2008 R2 will end. That means the end of regular security updates. However, if you move those SQL Server instances to Azure or Azure Stack (I will simply refer to both as Azure for the rest of the guide), Microsoft will give you three years of Extended Security Updates at no additional charge. If you are currently running SQL Server 2008/2008 R2 and you are unable to update to a later version of SQL Server before the July 9th deadline, you will want to take advantage of this offer rather than running the risk of facing a future security vulnerability. An unpatched instance of SQL Server could lead to data loss, downtime or a devastating data breach.

One of the challenges you will face when running SQL Server 2008/2008 R2 in Azure is ensuring high availability. On premises you may be running a SQL Server Failover Cluster (FCI) instance for high availability, or possibly you are running SQL Server in a virtual machine and are relying on VMware HA or a Hyper-V cluster for availability. When moving to Azure, none of those options are available. Downtime in Azure is a very real possibility that you must take steps to mitigate.

In order to mitigate the possibility of downtime and qualify for Azure’s 99.95% or 99.99% SLA, you have to leverage SIOS DataKeeper. DataKeeper overcomes Azure’s lack of shared storage and allows you to build a SQL Server FCI in Azure that leverages the locally attached storage on each instance. SIOS DataKeeper not only supports SQL Server 2008 R2 and Windows Server 2008 R2 as documented in this guide, it supports any version of Windows Server, from 2008 R2 through Windows Server 2019 and any version of SQL Server from from SQL Server 2008 through SQL Server 2019.

This guide will walk through the process of creating a two-node SQL Server 2008 R2 Failover Cluster Instance (FCI) in Azure, running on Windows Server 2008 R2. Although SIOS DataKeeper also supports clusters that span Availability Zones or Regions, this guide assumes each node resides in the same Azure Region, but different Fault Domains. SIOS DataKeeper will be used in place of the shared storage normally required to create a SQL Server 2008 R2 FCI.

Pre-Requisites

Active Directory
This guide assumes you have an existing Active Directory Domain. You can manage your own Domain Controllers or use Azure Active Directory Domain Services. For this tutorial we will connect to a domain called contoso.local. Of course you will connect to your own domain when following this tutorial.

Open Firewall Ports
– SQL Server:1433 for Default Instance
– Load Balancer Health Probe: 59999
– DataKeeper: these firewall rules are added to the Windows host based firewall automatically during installation. For details on which ports are opened consult the SIOS documentation.
– Keep in mind, if you have any network based security in place that blocks ports between the cluster nodes you will need to account for these ports there as well.

DataKeeper Service Account
Create a Domain account. We will specify this account when we install DataKeeper. This account will need to be added to the Local Administrators group on each node of the cluster.

Create the first SQL Server Instance in Azure

This guide will leverage the SQL Server 2008R2SP3 on Windows Server 2008R2 image that is published in the Azure Marketplace.

When you provision the first instance you will have to create a new Availability Set. During this process be sure to increase the number of Fault Domains to 3. This allows the two cluster nodes and the file share witness each to reside in their own Fault Domain.

If you don’t already have a virtual network configured, allow the creation wizard to create a new one for you.

Once the instance is created, go in to the IP configurations and make the Private IP address static. This is required for SIOS DataKeeper and is best practice for clustered instances.

Make sure that your virtual network is configured to set the DNS server to be a local Windows AD controller to ensure you will be able to join the domain in a later step.

After the virtual machines are provisioned, add at least two additional disks to each instance. Premium or Ultra SSD are recommended. Disable caching on the disks used for the SQL log files. Enable read-only caching on the disk used for the SQL data files. Refer to Performance guidelines for SQL Server in Azure Virtual Machines for additional information on storage best practices.

Create the 2nd SQL Server Instance in Azure

Follow the same steps as above, except be sure to place this instance in the same virtual network and Availability Set that you created with the 1st instance.

Create a File Share Witness (FSW) Instance

In order for the Windows Server Failover Cluster (WSFC) to work optimally you are required to create another Windows Server instance and place it in the same Availability Set as the SQL Server instances. By placing it in the same Availability Set you ensure that each cluster node and the FSW reside in different Fault Domains, ensuring your cluster stays on line should an entire Fault Domain go off line. This instances does not require SQL Server, it can be a simple Windows Server as all it needs to do is host a simple file share.

This instance will host the file share witness required by WSFC. This instance does not need to be the same size, nor does it require any additional disks to be attached. It’s only purpose is to host a simple file share. It can in fact be used for other purposes. In my lab environment my FSW is also my domain controller.

Uninstall SQL Server 2008 R2

Each of the two SQL Server instances provisioned already have SQL Server 2008 R2 installed on them. However, they are installed as standalone SQL Server instances, not clustered instances. SQL Server must be uninstalled from each of these instances before we can install the cluster instance. The easiest way to do that is to run the SQL Setup as shown below.

When you run setup.exe /Action-RunDiscovery you will see everything that is preinstalled

setup.exe /Action=RunDiscovery

Running setup.exe /Action=Uninstall /FEATURES=SQL,AS,RS,IS,Tools /INSTANCENAME=MSSQLSERVER kicks off the uninstall process

setup.exe /Action=Uninstall /FEATURES=SQL,AS,RS,IS,Tools /INSTANCENAME=MSSQLSERVER

Running setup.exe /Action-RunDiscovery confirms the uninstallation completed

setup.exe /Action-RunDiscovery

Run this uninstallation process again on the 2nd instance.

Add instances to the Domain

All three of these instances will need to be added to a Windows Domain. As mentioned in the Prerequisites section, you must have access to join an existing Windows Active Directory. In our case, we are joining a domain called contoso.local.

Add Windows Failover Clustering Feature

The Failover Clustering Feature needs to be added to the two SQL Server instances

Add-WindowsFeature Failover-Clustering

Install Convenience Rollup Update for Windows Server 2008 R2 SP1

There is a critical update ( kb2854082) that is required in order to configure a Windows Server 2008 R2 instance in Azure. That update and many more are included in the Convenience Rollup Update for Windows Server 2008 R2 SP1. Install this update on each of the two SQL Server instances.

Format the Storage

The additional disks that were attached when the two SQL Server instances were provisioned need to be formatted. Do the following for each volume on each instance.

Microsoft best practices says the following…

“NTFS allocation unit size: When formatting the data disk, it is recommended that you use a 64-KB allocation unit size for data and log files as well as TempDB.”

Run Cluster Validation

Run cluster validation to ensure everything is ready to be clustered.

Import-Module FailoverClusters
Test-Cluster -Node "SQL1", "SQL2"

Your report will contain WARNINGS about Storage and Networking. You can ignore those warnings as we know there are no shared disks and only a single network connection exists between the servers. You may also receive a warning about network binding order which can also be ignored. If you encounter any ERRORS you must address those before you continue.

Since there are no “Potential Cluster DIsks” available, the first test throws a warning and all the subsequent disks test are skipped. This is expected since we will be using just local disks replicated with SIOS DataKeeper.
The Validate Network Communication tests warn about just a single network being available between cluster nodes. You can ignore this warning since the network redundancy is handled at the virtual layer by Azure.

Error trying to run Cluster Validation?

I have encountered this error on a few occasions and I’m still trying to sort out under what conditions this occurs. Occasionally you will find that test-cluster fails to run as described in the forum post.

Test-Cluster
Unable to Validate a Cluster Configuration. The operation has failed. The action validate a configuration did not complete
There is an error in XML document (5, 73).  

Attempt by method

Microsoft.Xml.Serialzation.GeneratedAssembly.XmlSerialzationReaderClusterPrep.Config.Read4_As...Bolean) to access method

MS.Internal.ServerClusters.Validation.TestAssemblyCollection.Add(MS.Internal.ServerClusters.V....Failed

If this happens to you, I have found the following fix recommended in the forum post works for me.

Inside C:\Windows\System32\WindowsPowerShell\v1.0 make a copy of powershell_ise.exe.config file (make a copy inside C:\Windows\System32\WindowsPowerShell\v1.0)- rename it to powershell.exe.config

Open it with notepad- delete current config line and paste:
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
  <system.xml.serialization>
    <xmlSerializer useLegacySerializerGeneration="true"/>
  </system.xml.serialization>
</configuration>
- save and run test-cluster

While this fix will allow you to run test-cluster from Powershell, I have found that running Validate through the GUI still throws an error, even with this fix. I have a query in to Microsoft to see if they have a solution, but for now if you need to run cluster Validation you may have to use Test-Cluster in Powershell.

Create the Cluster

Best practices for creating a cluster in Azure would be to use Powershell to create a cluster, specifying a static IP address. Powershell allows us to specify a Static IP Address, whereas the GUI method does not. Unfortunately, Azure’s implementation of DHCP does not work well with WSFC, so if you use the GUI method you will wind up with a duplicate IP address as the Cluster IP Address that will need to be fixed before the cluster is usable.

However, what I have found is that the typical New-Cluster powershell command with the -StaticAddress command doesn’t work. To avoid the problem of the duplicate IP address, we have to resort to the cluster.exe utility and run the following command.

cluster /cluster:cluster1 /create /nodes:"sql1 sql2" /ipaddress:10.0.0.100/255.255.255.0

Add the File Share Witness

Next we need to add the File Share Witness. On the 3rd server we provisioned as the FSW, create a folder and share it as shown below. You will need to grant the Cluster Name Object (CNO) read/write permissions at both the Share and Security levels as shown below.

Once the share is created, run the Configure Cluster Quorum wizard on one of the cluster nodes and follow the steps illustrated below.

Install DataKeeper

Install DataKeeper on each of the two SQL Server cluster nodes as shown below.

This is where we will specify the Domain account we added to each of the local Domain Administrators group.

Configure DataKeeper

Once DataKeeper is installed on each of the two cluster nodes you are ready to configure DataKeeper.

NOTE – The most common error encountered in the following steps is security related, most often by pre-existing Azure Security groups blocking required ports. Please refer to the SIOS documentation to ensure the servers can communicate over the required ports.

First you must connect to each of the two nodes.

If everything is configured properly, you should then see the following in the Server Overview report.

Next, create a New Job and follow the steps illustrated below

Choose Yes here to register the DataKeeper Volume resource in Available Storage

Complete the above steps for each of the volumes. Once you are finished, you should see the following in the WSFC UI.

You are now ready to install SQL Server into the cluster.

NOTE – At this point the replicated volume is only accessible on the node that is currently hosting Available Storage. That is expected, so don’t worry!

Install SQL Server on the first node

If you want to script the installation, I have included the example below of a scripted cluster installation of SQL Server 2008 R2 into the first node of cluster. The script to add a node to existing cluster is found further down in the guide.

Of course adjust for your environment.

c:\SQLServerFull\setup.exe /q /ACTION=InstallFailoverCluster /FEATURES=SQL /INSTANCENAME="MSSQLSERVER" /INSTANCEDIR="C:\Program Files\Microsoft SQL Server" /INSTALLSHAREDDIR="C:\Program Files\Microsoft SQL Server" /SQLSVCACCOUNT="contoso\admin" /SQLSVCPASSWORD="xxxxxxxxx" /AGTSVCACCOUNT="contoso\admin" /AGTSVCPASSWORD="xxxxxxxxx" /SQLDOMAINGROUP="contoso\SQLAdmins" /AGTDOMAINGROUP="contoso\SQLAdmins" /SQLCOLLATION="SQL_Latin1_General_CP1_CI_AS" /FAILOVERCLUSTERGROUP="SQL Server 2008 R2 Group" /FAILOVERCLUSTERDISKS="DataKeeper Volume E" "DataKeeper Volume F" /FAILOVERCLUSTERIPADDRESSES="IPv4;10.0.0.101;Cluster Network 1;255.255.255.0" /FAILOVERCLUSTERNETWORKNAME="SQL2008Cluster" /SQLSYSADMINACCOUNTS="contoso\admin" /SQLUSERDBLOGDIR="E:\MSSQL10.MSSQLSERVER\MSSQL\Log" /SQLTEMPDBLOGDIR="F:\MSSQL10.MSSQLSERVER\MSSQL\Log" /INSTALLSQLDATADIR="F:\MSSQL10.MSSQLSERVER\MSSQLSERVER" /IAcceptSQLServerLicenseTerms

If you prefer to use the GUI, just follow along with the screenshots below.

On the first node, run the SQL Server setup.

Choose New SQL Server Failover Cluster Installation and follow the steps as illustrated.

Choose only the options you need.

Please note, this document assumes you are using the Default instance of SQL Server. If you use a Named Instance you need to make sure you lock down the port that it listens on, and use that port later on when you configure the load balancer. You also will need to create a load balancer rule for the SQL Server Browser Service (UDP 1434) in order to connect to a Named Instance. Neither of those two requirements are covered in this guide, but if you require a Named Instance it will work if you do those two additional steps.

Here you will need to specify an unused IP address

Go to the Data Directories tab and relocate data and log files. At the end of this guide we talk about relocating tempdb to a non-mirrored DataKeeper Volume for optimal performance. For now, just keep it on one of the clustered disks.

Install SQL Server on the second node

Below is an example of the command you can run to add an additional SQL Server 2008 R2 node into an existing cluster.

c:\SQLServerFull\setup.exe /q /ACTION=AddNode /INSTANCENAME="MSSQLSERVER" /SQLSVCACCOUNT="contoso\admin" /SQLSVCPASSWORD="xxxxxxxxx" /AGTSVCACCOUNT="contoso\admin" /AGTSVCPASSWORD="xxxxxxxx" /IAcceptSQLServerLicenseTerms

If you prefer using the GUI, follow along with the following screenshots.

Run the SQL Server setup again on the second node and choose Add node to a SQL Server Failover Cluster.

Congratulations, you are almost done! However, due to Azure’s lack of support for gratuitous ARP, we will need to configure an Internal Load Balancer (ILB) to assist with client redirection as shown in the following steps.

Update the SQL Cluster IP Address

In order for the ILB to function properly, you must run run the following command from one of the cluster nodes. It SQL Cluster IP enables the SQL Cluster IP address to respond to the ILB health probe while also setting the subnet mask to 255.255.255.255 in order to avoid IP address conflicts with the health probe.

cluster res <IPResourceName> /priv enabledhcp=0 address=<ILBIP> probeport=59999  subnetmask=255.255.255.255

NOTE – I don’t know if it is a fluke, but on occasion I have run this command and it looks like it runs, but it doesn’t complete the job and I have to run it again. The way I can tell if it worked is by looking at the Subnet Mask of the SQL Server IP Resource, if it is not 255.255.255.255 then you know it didn’t run successfully.  It may simple be a GUI refresh issue, so you can also try restarting the cluster GUI to verify the subnet mask was updated.

After it runs successfully, take the resource offline and bring it back online for the changes to take effect.

Create the Load Balancer

The final step is to create the load balancer. In this case we are assuming you are running the Default Instance of SQL Server, listening on port 1433.

The Private IP Address you define when you Create the load balancer will be the exact same address your SQL Server FCI uses.

Add just the two SQL Server instances to the backend pool. Do NOT add the FSW to the backend pool.

In this load balancing rule you must enable Floating IP

Validate the Cluster

Before you continue, run cluster validation one more time. The Cluster Validation report should return just the same network and storage warnings that it did the first time you ran it. Assuming there are no new errors or warnings, your cluster is configured correctly.

Edit sqlserv.exe Config File

In directory C:\Program Files (x86)\Microsoft SQL Server\100\Tools\Binn we created a sqlps.exe.config file and sqlservr.exe.config with the following lines in the config file:

<configuration>
  <startup>
    <supportedRuntime version="v2.0.50727"/>
  </startup>
</configuration>

These files, by default, will not exist and may be created. If this file(s) already exists for your installation, the <supportedRuntime version=”v2.0.50727″/> line simply needs to be placed with the <startup>…</startup> sub-section of the <configuration>…</configuration> section. This should be done on both servers.

Test the Cluster

The most simple test is to open SQL Server Management Studio on the passive node and connect to the cluster. If you are able to connect, congratulations, you did everything correct! If you can’t connect don’t fear, you wouldn’t be the first person to make a mistake. I wrote a blog article to help troubleshoot the issue. Managing the cluster is exactly the same as managing a traditional shared storage cluster. Everything is controlled through Failover Cluster Manager.

Optional – Relocate Tempdb

For optimal performance it would be advisable to move tempdb to the local, non replicated, SSD. However, SQL Server 2008 R2 requires tempdb to be on a clustered disk. SIOS has a solution called a Non-Mirrored Volume Resource which addresses this issue. It would be advisable to create a non-mirrored volume resource of the local SSD drive and move tempdb there. However, the local SSD drive is non-persistent, so you must take care to ensure the folder holding tempdb and the permissions on that folder are recreated each time the server reboots.

After you create the Non-Mirrored Volume Resource of the local SSD, follow the steps in this article to relocate tempdb. The startup script described in that article must be added to each cluster node.

For More Information

As always, if you have questions or comments you can leave them in the comment section below or reach me on Twitter @daveberm

STEP-BY-STEP: HOW TO CONFIGURE A SQL SERVER 2008 R2 FAILOVER CLUSTER INSTANCE ON WINDOWS SERVER 2008 R2 IN AZURE OR AZURE STACK

Achieving SQL Server HA/DR with a mix of Always On Availability Groups and SANless SQL Server Failover Cluster Instances

Introduction

The topic of mixing SQL Server Failover Cluster Instances (FCI) with Always On Availability Groups (AG) is pretty well documented. However, most of the available documentation documents configurations that assume the SQL Server FCI portion of the solution utilizes shared storage. What if I want to build a SANless SQL Server FCI using Storage Spaces Direct (S2D), can I still add a SQL Server AG to the mix? Unfortunately, the answer to this question is no. As of today, this combination of S2D based SQL Server FCI and Always On AG is not supported. I previously blogged about this S2D limitation here.

However, the good news is you CAN build a SANless SQL Server FCI with SIOS DataKeeper and still leverage Always On AG for things like readable secondaries. You still have to abide by the same rules that apply when mixing traditional SAN based SQL Server FCI and Always On AGs, but other than that it is exactly the same….mostly.

DataKeeper Synchronous replication is commonly used between nodes in the same data center or cloud region, but you may want to replicate asynchronously to an additional node in a different region for disaster recovery. In this case, if you ever do have to bring the DR node online after an unexpected failure, you will have to scrap the Always On AG configurations and reconfigure them. This requirement is very similar to to what Microsoft published here in regards to restoring asynchronous snapshots of SQL Server Always On AGs running inside VMs.

Availability Groups

Essentially, a SANLess SQL Server FCI w/DataKeeper looks like a single instance of SQL Server as far as the Always On Availability Group Wizard is concerned. The configuration of the Always On AG is exactly the same as if you were creating just an Always On AG between two Standalone (non-clustered) SQL Server instances.

The real confusion arise in the fact that in this configuration all the servers reside in the same failover cluster, but the SQL Server FCI is only configured to run only on the cluster nodes where SQL Server was installed as a Clustered SQL Server Instance. The other nodes are in the same cluster, but SQL is installed on those nodes as a Standalone SQL Server Instance, not a Clustered Instance. It’s a bit confusing, but what is happening is that Always On AG’s leverage the WSFC quorum model and listeners, so all the AG Replicas need to reside in the same WSFC, even though they typically do not run clustered instances of SQL Server. If you are completely confused that is okay, most people are confused when they first try to wrap their head around this hybrid configuration.

The real benefit in a configuration like this is that a SQL Server FCI can be a better and more cost effective (more on this later*) HA solution than Always On AG in many circumstances, but it lacks the ability to offer a readable secondary replica. Adding an Always On AG readable secondary replica becomes a viable option to address this need. And using SIOS DataKeeper eliminates the need for a SAN for the SQL Server FCI, which opens up the possibility of configuring SQL Server FCIs where nodes reside in different data center, which also means support for SQL Server FCI’s that span Availability Zones in both Azure and AWS.

Please note that pictured below is just one possible configuration. Multiple FCI cluster nodes, multiple AGs and multiple Replicas are all supported. You are only limited by the limits imposed by your version of SQL Server.

This article seems to document the setup steps pretty well. Of course, instead of shared storage for the SQL FCI, you will use SIOS DataKeeper to build the FCI as I document here.

Image result for SQL Server FCI with Availability Groups

Basic Availability Groups

As of SQL Server 2016 a scaled down “Basic Availability Groups” became available in SQL Server Standard Edition, making this configuration possible even in SQL Server Standard Edition. Basic AGs are limited to a single database per Availability Group, a Single Replica (2-nodes). However, they do not support a readable secondary replica so their use cases in this hybrid configuration are very limited.

Distributed Availability Groups

Distributed AGs were introduced in SQL Server 2016 are also supported in this hybrid configuration. Distributed AGs are very similar to regular AGs, but the Replicas do not need to reside in the same cluster, or even in the same Windows Domain. Microsoft documents the the main use cases of Distributed Availability Groups as follows:

  • Disaster recovery and easier multi-site configurations
  • Migration to new hardware or configurations, which might include using new hardware or changing the underlying operating systems
  • Increasing the number of readable replicas beyond eight in a single availability group by spanning multiple availability groups
Image result for distributed availability groups

Summary

If you like the idea of SQL Server FCIs for high availability, but want the flexibility of read-only secondary replicas, this hybrid solution might just be the thing you are looking for. Traditional SAN baseds SQL Server FCIs, and even Storage Spaces Direct (S2D) based FCIs, limit you to a single data center. SIOS DataKeeper frees you from the limits of your SAN and enables configurations such as SQL Server FCI that span Availability Zones or Cloud Regions. It also eliminates the reliance on the SAN, allowing you to leverage locally attached high speed storage devices without giving up your SQL Server FCI.

* How to Save Money

Earlier I promised I would tell you how to save money by doing this all with SQL Server Standard Edition. If you can live with readable replicas that are point in time based snapshots, you can skip Always On AGs completely and just use the SIOS DataKeeper target side snapshot feature to periodically take an application consistent snapshot of the volumes on the target server without impacting ongoing replication or availability. Here’s how…

http://discover.us.sios.com/rs/siostechnology/images/10-Ways-Save-AlwaysOn-vs-Failover-Clustering.pdf

Create a 2-node SQL Server FCI with SQL Server Standard Edition and save a boatload of money on SQL licenses, but yet still replicate the data to a 3rd node outside the cluster for reporting or DR purposes. If you take a snapshot of the volumes on this third server these snapshots are read-right accessible, so you can mount those databases from a standalone instance of SQL Server to run month end reports, copy to archives, or you might even want to use those snapshot to quickly and easily update your QA and Test/Dev environments with the latest SQL data.

I hope you found this helpful and informative. As always, if you have questions, add them here or reach me on Twitter @daveberm

Achieving SQL Server HA/DR with a mix of Always On Availability Groups and SANless SQL Server Failover Cluster Instances

Configure SQL Server Failover Cluster Instance on Azure Virtual Machines with MSDTC #SQL #Azure #MSDTC

If you have been following my blog, you probably know that I write a lot of step-by-step guides for building SQL Server Failover Cluster Instances (FCI) on Azure, from SQL Server 2008 through the lastest. Here are some links to get you started, but really there is very little difference in the configuration between the different versions of Windows and SQL Server, so I think you will be able to figure it out regardless of what versions you use.

STEP-BY-STEP: HOW TO CONFIGURE A SQL SERVER FAILOVER CLUSTER INSTANCE (FCI) IN MICROSOFT AZURE IAAS #SQLSERVER #AZURE #SANLESS

STEP-BY-STEP: HOW TO CONFIGURE A SQL SERVER 2008 R2 FAILOVER CLUSTER INSTANCE IN AZURE

What I have not addressed is what to do about MSDTC. Microsoft addressed that in this article posted here.

https://blogs.msdn.microsoft.com/sql_pfe_blog/2018/07/05/configure-sql-server-failover-cluster-instance-on-azure-virtual-machines-with-msdtc

However, that article/video only addresses SQL Server 2016 and later. The good news is that most of that guidance can be applied to SQL Server 2008/2012/2014. Until I have time to do a proper step-by-step guide I wanted to jot down some basic notes, more as a reminder to myself, but you might find this information useful as well in the meantime.

The steps below assume you have already created a SQL Server FCI in Azure and clustered the DTC resource. Reference the guides above for the details on those steps. The steps below really just detail the load balancer configuration required in Azure to make this work.

Create Load Balancer for MSDTC

The MSDTC resource will require its own load balancer. Instead of creating a new load balancer, we will add a new frontend to the load balancer that should already be configured for the SQL Server FCI. Of course this frontend IP address should match the cluster IP address associated with the clustered MSDTC resource.

For the backend pool just reuse the existing pool that you created that contains the SQL cluster nodes.

You will need to create a new health probe dedicated to the MSDTC resource. The port you use has to be different than the one you used for the SQL resource, so don’t use 59999. Instead maybe use something like 49999.

The final step is to create the load balancing rule for MSDTC. Create a new rule and reference the MSDTC frontend that we just created and the existing backend. Next we need to create a new load balancing rule. Since MSDTC uses ephemeral ports, which is a big range of ports, when you create the rule you have to select the box that says “HA Ports”. And finally make sure Direct Server Return is enabled.

Update MSDTC Cluster IP Resource

Just like our SQL Server Cluster IP address, we need to run a Powershell command that will for the MSDTC cluster IP resource to respond to the health probe we just created that probes port 49999. It also sets the subnet mask of that MSDTC cluster IP address to 255.255.255.255 to avoid IP address conflicts with the load balancer frontend we setup that shares the same address.

# Define variables $ClusterNetworkName = “”  
# the cluster network name (Use Get-ClusterNetwork on Windows Server 2012 of higher to find the name of the MSDTC resource) $IPResourceName = “”  
# the IP Address resource name of the MSDTC resource  $ILBIP = “”  
# the IP Address of the Internal Load Balancer (ILB) and MSDTC resource 
Import-Module FailoverClusters 
# If you are using Windows Server 2012 or higher: 
Get-ClusterResource $IPResourceName | Set-ClusterParameter -Multiple @{Address=$ILBIP;ProbePort=49999;SubnetMask="255.255.255.255";Network=$ClusterNetworkName;EnableDhcp=0} 
# If you are using Windows Server 2008 R2 use this:  
#cluster res $IPResourceName /priv enabledhcp=0 address=$ILBIP probeport=59999  subnetmask=255.255.255.255

Confirm it is working!

You can use DTCPing or go into Component Services and look under Computers>My Computers>Distributed Transaction Coordinator where you should see a local DTC and a clustered DTC. Any distributed transactions should appear in the clustered DTC, not the local DTC. Check out this video for an example of how to create a distributed transaction for testing.

Next Steps

This is a quick and dirty guide, but for the experienced user it should get your MSDTC resource up and running in Azure. I’ll be publishing a detailed step-by-step guide in the near future. In the meantime, if you get stuck don’t hesitate to reach out to me on Twitter @daveberm

For more information visit https://us.sios.com/solutions/cloud-high-availability/azure/

Configure SQL Server Failover Cluster Instance on Azure Virtual Machines with MSDTC #SQL #Azure #MSDTC

Step-by-Step: How to configure a SQL Server 2008 R2 Failover Cluster Instance in Azure

Introduction

If you are reading this article you probably are still using SQL Server 2008/2008 R2 and want to take advantage of the extended security updates that Microsoft is offering if you move your SQL Server 2008/2008 R2 into Azure. I previously wrote about this topic in this blog post.

You may be wondering how to make sure your SQL Server instance remains highly available once you make the move to Azure. Today, most people have business critical SQL Server 2008/2008 R2 configured as a clustered instance (SQL Server FCI) in their data center. When looking at Azure you have probably come to the realization that due to the lack of shared storage it might seem that you can’t bring your SQL Server FCI to the Azure cloud. However, that is not the case thanks to SIOS DataKeeper.

SIOS DataKeeper enables you to build a SQL Server FCI in Azure, AWS, Google Cloud, or anywhere else where shared storage is not available or where you wish to configure multi-site clusters where shared storage doesn’t make sense. DataKeeper has been enabling SANless clusters for WIndows and Linux since 1999. Microsoft documents the use of SIOS DataKeeper for SQL Server FCI in their documentation: High availability and disaster recovery for SQL Server in Azure Virtual Machines.

I’ve written about SQL Server FCI’s running in Azure before, but I never published a Step-by-Step Guide specific to SQL Server 2008/2008 R2. The good news is that it works just as great with SQL 2008/2008 R2 as it does with SQL 2012/2014/2016/2017 and the soon to be released 2019. Also, regardless of the version of Windows Server (2008/2012/2016/2019) or SQL Server (2008/2012/2014/2016/2017) the configuration process is similar enough that this guide should be sufficient enough to get you through any configurations.

If your flavor of SQL or Windows is not covered in any of my guides, don’t be afraid to jump in and build a SQL Server FCI and reference this guide, I think you will figure out any differences and if you ever get stuck just reach out to me on Twitter @daveberm and I’ll be glad to give you a hand.

This guide uses SQL Server 2008 R2 with Windows Server 2012 R2. As of the time of this writing I did not see an Azure Marketplace image of SQL 2008 R2 on Windows Server 2012 R2, so I had to download and install SQL 2008 R2 manually. Personally I prefer this combination, but if you need to use Windows Server 2008 R2 or Windows 212 that is fine. If you use Windows Server 2008 R2 don’t forget to install the kb3125574 Convenience Rollup Update for Windows Server 2008 R2 SP1. Or if you are stuck with Server 2012 (not R2) you need the Hotfix in kb2854082.

Don’t be fooled by this article that says you must install kb2854082 on your SQL Server 2008 R2 instances. If you start searching for that update for Windows Server 2008 R2 you will find that only the version for Server 2012 is available. That particular hotfix for Server 2008 R2 is instead included in the rollup Convenience Rollup Update for Windows Server 2008 R2 SP1.

Provision Azure Instances

I’m not going to go into great detail here with a bunch of screenshots, especially since the Azure Portal UI tends to change pretty frequently, so any screenshots I take will get stale pretty quickly. Instead, I will just cover the important topics that you should be aware of.

Fault Domains or Availability Zones?

In order to ensure your SQL Server instances are highly available, you have to make sure your cluster nodes reside in different Fault Domains (FD) or in different Availability Zones (AZ). Not only do your instances need to reside in different FDs or AZs, but your File Share Witness (see below) also needs to reside in a FD or AZ that is different than that one your cluster nodes reside in.

Here is my take on it. AZs are the newest Azure feature, but they are only supported in a handful of regions so far. AZs give you a higher SLA (99.99%) then FDs (99.95%), and protect you against the kind of cloud outages I describe in my post Azure Outage Post-Mortem. If you can deploy in a region that supports AZs then I recommend you use AZs.

In this guide I used AZs which you will see when you get to the section on configuring the load balancer. However, if you use FDs everything will be exactly the same, except the load balancer configuration will reference Availability Sets rather than Availability Zones.

What is a File Share Witness you ask?

Without going into great detail, Windows Server Failover Clustering (WSFC) requires you configure a “Witness” to ensure failover behaves properly. WSFC supports three kinds of witnesses: Disk, File Share, Cloud. Since we are in Azure a Disk Witness is not possible. Cloud Witness is only available with Windows Server 2016 and later, so that leaves us with a File Share Witness. If you want to learn more about cluster quorums check out my post on the Microsoft Press Blog, From the MVPs: Understanding the Windows Server Failover Cluster Quorum in Windows Server 2012 R2

Add storage to your SQL Server instances

As you provision your SQL Server instances you will want to add additional disks to each instance. Minimally you will need one disk for the SQL Data and Log file, one disk for Tempdb. Whether or not you should have a seperate disk for log and data files is somewhat debated when running in the cloud. On the back end the storage all comes from the same place and your instance size limits your total IOPS. In my opinion there really isn’t any value in separating your log and data files since you cannot ensure that they are running on two physical sets of disks. I’ll leave that for you to decide, but I put log and data all on the same volume.

Normally a SQL Server 2008 R2 FCI would require you to put tempdb on a clustered disk. However, SIOS DataKeeper has this really nifty feature called a DataKeeper Non-Mirrored Volume Resource. This guide does not cover moving tempdb to this non-mirrored volume resource, but for optimal performance you should do this. There really is no good reason to replicate tempdb since it is recreated upon failover anyway.

As far as the storage is concerned you can use any storage type, but certainly use Managed Disks whenever possible. Make sure each node in the cluster has the identical storage configuration. Once you launch the instances you will want to attach these disks and format them NTFS. Make sure each instance uses the same drive letters.

Networking

It’s not a hard requirement, but if at all possible use an instance size that supports accelerated networking. Also, make sure you edit the network interface in the Azure portal so that your instances use a static IP address. For clustering to work properly you want to make sure you update the settings for the DNS server so that it points to your Windows AD/DNS server and not just some public DNS server.

Security

By default, the communications between nodes in the same virtual network are wide open, but if you have locked down your Azure Security Group you will need to know what ports must be open between the cluster nodes and adjust your security group. In my experience, almost all the issues you will encounter when building a cluster in Azure are either caused by blocked ports.

DataKeeper has some some ports that are required to be open between the clustered instance. Those ports are as follows:
UDP: 137, 138
TCP: 139, 445, 9999, plus ports in the 10000 to 10025 range

Failover cluster has its own set of port requirements that I won’t even attempt to document here. This article seems to have that covered. http://dsfnet.blogspot.com/2013/04/windows-server-clustering-sql-server.html

In addition, the Load Balancer described later will use a probe port that must allow inbound traffic on each node. The port that is commonly used and described in this guide is 59999.

And finally if you want your clients to be able to reach your SQL Server instance you want to make sure your SQL Server port is open, which by default is 1433.

Remember, these ports can be blocked by the Windows Firewall or Azure Security Groups, so to be sure to check both to ensure they are accessible.

Join the Domain

A requirement for SQL Server 2008 R2 FCI is that the instances must reside in the same Windows Server Domain. So if you have not done so, make sure you have joined the instances to your Windows domain

Local Service Account

When you install DataKeeper it will ask you to provide a service account. You must create a domain user account and then add that user account to the Local Administrators Group on each node. When asked during the DataKeeper installation, specify that account as the DataKeeper service account. Note – Don’t install DataKeeper just yet!

Domain Global Security Groups

When you install SQL 2008 R2 you will be asked to specify two Global Domain Security Groups. You might want to look ahead at the SQL install instructions and create those groups now. You will also want to create a domain user account and place them in each of these security accounts. You will specify this account as part of the SQL Server Cluster installation.

Other Pre-Requisites

You must enable both Failover Clustering and .Net 3.5 on each instance of the two cluster instances. When you enable Failover Clustering, also be sure to enable the optional “Failover Cluster Automation Server” as it is required for a SQL Server 2008 R2 cluster in Windows Server 2012 R2.

Create the Cluster and DataKeeper Volume Resources

We are now ready to start building the cluster. The first step is to create the base cluster. Because of the way Azure handles DHCP, we MUST create the cluster using Powershell and not the Cluster UI. We use Powershell because it will let us specify a static IP address as part of the creation process. If we used the UI it would see that the VMs use DHCP and it will automatically assign a duplicate IP address, so we we want to avoid that situation by using Powershell as shown below.

New-Cluster -Name cluster1 -Node sql1,sql2 -StaticAddress 10.0.0.100 -NoStorage

After the cluster creates, run Test-Cluster. This is required before SQL Server will install.

Test-Cluster

You will get warnings about Storage and Networking, but you can ignore those as they are expected in a SANless cluster in Azure. If there are any other warnings or errors you must address those before moving on.

After the cluster is created you will need to add the File Share Witness. On the third server we specified as the file share witness, create a file share and give Read/Write permissions to the cluster computer object we just created above. In this case $Cluster1 will be the name of the computer object that needs Read/Write permissions at both the share and NTFS security level.

Once the share is created, you can use the Configure Cluster Quorum Wizard as shown below to configure the File Share Witness.

Install DataKeeper

It is important to wait until the basic cluster is created before we install DataKeeper since the DataKeeper installation registers the DataKeeper Volume Resource type in failover clustering. If you jumped the gun and installed DataKeeper already that is okay. Simply run the setup again and choose Repair Installation.

The screenshots below walk you through a basic installation. Start by running the DataKeeper Setup.

The account you specify below must be a domain account and must be part of the Local Administrators group on each of the cluster nodes.

When presented with the SIOS License Key manager you can browse out to your temporary key, or if you have a permanent key you can copy the System Host ID and use that to request your permanent license. If you ever need to refresh a key the SIOS License Key Manager is a program that will be installed that you can run separately to add a new key.

Create DataKeeper Volume Resource

Once DataKeeper is installed on each node you are ready to create your first DataKeeper Volume Resource. The first step is to open the DataKeeper UI and connect to each of the cluster nodes.

If everything is done correctly the Server Overview Report should look something like this.

You can now create your first Job as shown below.

After you choose a Source and Target you are presented with the following options. For a local target in the same region the only thing you need to select is Synchronous.

Choose Yes and auto-register this volume as a cluster resource.

Once you complete this process open up the Failover Cluster Manager and look in Disk. You should see the DataKeeper Volume resource in Available Storage. At this point WSFC treats this as if it were a normal cluster disk resource.

Slipstream SP3 onto SQL 2008 R2 install media

SQL Server 2008 R2 is only supported on Windows Server 2012 R2 with SQL Server SP2 or later. Unfortunately, Microsoft never released a SQL Server 2008 R2 installation media that that includes SP2 or SP3. Instead, you must slipstream the service pack onto the installation media BEFORE you do the installation. If you try to do the installation with the standard SQL Server 2008 R2 media you will run into all kinds of problems. I don’t remember the exact errors you will see, but I do recall they didn’t really point to the exact problem and you will waste a lot of time trying to figure out what went wrong.

As of the date of this writing, Microsoft does not have a Windows Server 2012 R2 with SQL Server 2008 R2 offering in the Azure Marketplace, so you will be bringing your own SQL license if you want to run SQL 2008 R2 on Windows Server 2012 R2 in Azure. If they add that image later, or if you choose to use the SQL 2008 R2 on Windows Server 2008 R2 image you must first uninstall the existing standalone instance of SQL Server before moving forward.

I followed the guidance in Option 1 of this article to slipstream SP3 on onto my SQL 2008 R2 installation media. You will of course have to adjust a few things as this article references SP2 instead of SP3. Make sure you slipstream SP3 on the installation media we will use for both nodes of the cluster. Once that is done, continue to the next step.

Install SQL Server on the First Node

Using the SQL Server 2008 R2 media with SP3 slipstreamed, run setup and install the first node of the cluster as shown below.

If you use anything other than the Default instance of SQL Server you will have some additional steps not covered in this guide. The biggest difference is you must lock down the port that SQL Server uses since by default a named instance of SQL Server does NOT use 1433. Once you lock down the port you also need to specify that port instead of 1433 whenever we reference port 1433 in this guide, including the firewall setting and the Load Balancer settings.

Here make sure to specify a new IP address that is not in use. This is the same IP address we will use later when we configure the Internal Load Balancer later.

As I mentioned earlier, SQL Server 2008 R2 utilizes AD Security Groups. If you have not already created them, go ahead and create them now as show below before you continue to the next step in the SQL install

Specify the Security Groups you created earlier.

Make sure the service accounts you specify are a member of the associated Security Group.

Specify your SQL Server administrators here.

If everything goes well you are now ready to install SQL Server on the second node of the cluster.

Install SQL Server on the Second Node

One the second node, run the SQL Server 2008 R2 with SP3 install and select Add Node to a SQL Server FCI.

Proceed with the installation as shown in the following screenshots.

Assuming everything went well, you should now have a two node SQL Server 2008 R2 cluster configured that looks something like the following.

However, you probably will notice that you can only connect to the SQL Server instance from the active cluster node. The problem is that Azure does not support gratuitous ARP, so your clients cannot connect directly to the Cluster IP Address. Instead, the clients must connect to an Azure Load Balancer, which will redirect the connection to the active node. To make this work there are two steps: Create the Load Balancer and Fix the SQL Server Cluster IP to respond to the Load Balancer Probe and use a 255.255.255.255 Subnet mask. Those steps are described below.

Before you continue, run cluster validation one more time. The Cluster Validation report should return just the same network and storage warnings that it did the first time you ran it. Assuming there are no new errors or warnings, your cluster is configured correctly.

Edit sqlserv.exe Config File

include the below lines in the sqlservr.exe.config file. This forces SQL Server to use the right CLR integration.

<configuration>
  <startup>
    <supportedRuntime version="v2.0.50727"/>
  </startup>
</configuration>

The file, by default, will not exist and may be created. If this file already exists for your installation, the <supportedRuntime version=”v2.0.50727″/> line simply needs to be placed with the <startup>…</startup> sub-section of the <configuration>…</configuration> section.

Create the Azure Load Balancer

I’m going to assume your clients can communicate directly to the internal IP address of the SQL cluster so we will create an Internal Load Balancer (ILB) in this guide. If you need to expose your SQL Instance on the public internet you can use a Public Load Balancer instead.

In the Azure portal create a new Load Balancer following the screenshots as shown below. The Azure portal UI changes rapidly, but these screenshots should give you enough information to do what you need to do. I will call out important settings as we go along.

Here we create the ILB. The important thing to note on this screen is you must select “Static IP address assignment” and specify the same IP address that we used during the SQL Cluster installation.

Since I used Availability Zones I see Zone Redundant as an option. If you used Availability Sets your experience will be slightly different.

In the Backend pool be sure to select the two SQL Server instances. You DO NOT want to add your File Share Witness in the pool.

Here we configure the Health Probe. Most Azure documentation has us using port 59999, so we will stick with that port for our configuration.

Here we will add a load balancing rule. In our case we want to redirect all SQL Server traffic to TCP port 1433 of the active node. It is also important that you select Floating IP (Direct Server Return) as Enabled.

Run Powershell Script to Update SQL Client Access Point

Now we must run a Powershell script on one of the cluster nodes to allow the Load Balancer Probe to detect which node is active. The script also sets the Subnet Mask of the SQL Cluster IP Address to 255.255.255.255.255 so that it avoids IP address conflicts with the Load Balancer we just created.

# Define variables
$ClusterNetworkName = “” 
# the cluster network name (Use Get-ClusterNetwork on Windows Server 2012 of higher to find the name)
$IPResourceName = “” 
# the IP Address resource name 
$ILBIP = “” 
# the IP Address of the Internal Load Balancer (ILB) and SQL Cluster
Import-Module FailoverClusters
# If you are using Windows Server 2012 or higher:
Get-ClusterResource $IPResourceName | Set-ClusterParameter -Multiple @{Address=$ILBIP;ProbePort=59999;SubnetMask="255.255.255.255";Network=$ClusterNetworkName;EnableDhcp=0}
# If you are using Windows Server 2008 R2 use this: 
#cluster res $IPResourceName /priv enabledhcp=0 address=$ILBIP probeport=59999  subnetmask=255.255.255.255

This is what the output will look like if run correctly.

You probably notice that the end of that script has a commented line of code to use if you are running on Windows Server 2008 R2. If you are running Windows Server 2008 R2 make sure you run the code specific for Windows Server 2008 R2 at a Command prompt, it is not Powershell.

Next Steps

If you get to this point and you still cannot connect to the cluster remotely you wouldn’t be the first person. There are a lot of things that can go wrong in terms of security, load balancer, SQL ports, etc. I wrote this guide to help troubleshoot connection issues.

In fact, in this very installation I ran into some strange issues in terms of my SQL Server TCP/IP Properties in SQL Server Configuration Manager. When I looked at the properties I did not see the SQL Server Cluster IP address as one of the addresses it was listening on, so I had to add it manually. I’m not sure if that was an anomaly, but it certainly was an issue I had to resolve before I could connect to the cluster from a remote client.

As I mentioned earlier, one other improvement you can make to this installation is to use a DataKeeper Non-Mirrored Volume Resource for TempDB. If you set that up please be aware of the following two configuration issues people commonly run into.

The first issue is if you move tempdb to a folder on the 1st node, you must be sure to create the exact same folder structure on the second node. If you don’t do that when you try to failover SQL Server will fail to come online since it can’t create TempDB

The second issue occurs anytime you add another DataKeeper Volume Resource to a SQL Cluster after the cluster is created. You must go into the properties of the SQL Server cluster resource and make it dependent on the new DataKeeper Volume resource you added. This is true for the TempDB volume and any other volumes you may decide to add after the cluster is created.

If you have any questions about this configuration or any other cluster configurations please feel free to reach out to me on Twitter @DaveBerm.

https://clusteringformeremortals.com/2016/01/06/troubleshooting-azure-ilb-connection-issues-in-a-sql-server-alwayson-fci-cluster/

Step-by-Step: How to configure a SQL Server 2008 R2 Failover Cluster Instance in Azure

Azure Outage Post-Mortem Part 3

My previous blog posts, Azure Outage Post-Mortem – Part 1 and Azure Outage Post-Mortem Part 2,made some assumptions based upon limited information coming from blog posts and twitter. I just attended a session at Ignite which gave a little more clarity as to what actually happened. Sometime tomorrow you should be able to view the session for yourself.

BRK3075 – Preparing for the unexpected: Anatomy of an Azure outage

The official Root Cause Analysis they said will be published soon, but in the meantime here are some tidbits of information gleaned from the session.

The outage was NOT caused by a lightning strike as previously reported. Instead, due to the nature of the storm there were electrical storm sags and swells, which locked out a chiller plant in the 1st datacenter. During this first outage they were able to recover the chiller quickly with no noticeable impact. Shortly thereafter, there was a second outage at a second datacenter which was not recovered properly, which began an unfortunate series of events.

During this 2nd outage, Microsoft states that “Engineers didn’t triage alerts correctly – chiller plant recovery was not prioritized”. There were numerous alerts being triggered at this time, and unfortunately the chiller being offline did not receive the priority it should have. The RCA as to why that happened is still being investigated.

Microsoft states that of course redundant chiller systems are in place. However, the cooling systems were not set to automatically failover. Recently installed new equipment had not been fully tested, so it was set to manual mode until testing had been completed.

After 45 minutes the ambient cooling failed, hardware shutdown, air handlers shut down because they thought there was a fire, and staff had been evacuated due to the false fire alarm. During this time temperature in the data center was increasing and some hardware was not shut down properly, causing damage to some storage and networking.

After manually resetting the chillers and opening the air handlers the temperature began to return to normal. It took about 3 hours and 29 minutes before they had a complete picture of the status of the datacenter.

The biggest issue was there was damage to storage. Microsoft’s primary concern is data protection, so short of the enter datacenter sinking into a sinkhole or a meteor strike taking out the datacenter, Microsoft will work to recover data to ensure no data loss. This of course took some time, which extend the overall length of the outage. The good news is that no customer data was lost, the bad news is that it seemed like it took 24-48 hours for things to return to normal, based upon what I read on Twitter from customers complaining about the prolonged outage.

Everyone expected that this outage would impact customers hosted in the South Central Region, but what they did not expect was that the outage would have an impact outside of that region. In the session, Microsoft discusses some of the extended reach of the outage.

Azure Service Manager (ASM) – This controls Azure “Classic” resources, AKA, pre-ARM resources. Anyone relying on ASM could have been impacted. It wasn’t clear to me why this happened, but it appears that South Central Region hosts some important components of that service which became unavailable.

Visual Studio Team Service (VSTS) – Again, it appears that many resources that support this service are hosted in the South Central Region. This outage is described in great detail by Buck Hodges (@tfsbuck), Director of Engineering, Azure DevOps this blog post.

Postmortem: VSTS 4 September 2018

Azure Active Directory (AAD) – When the South Central region failed, AAD did what it was designed to due and started directing authentication requests to other regions. As the East Coast started to wake up and online, authentication traffic started picking up. Now normally AAD would handle this increase in traffic through autoscaling, but the autoscaling has a dependency on ASM, which of course was offline. Without the ability to autoscale, AAD was not able to handle the increase in authentication requests. Exasperating the situation was a bug in Office clients which made them have very aggressive retry logic, and no backoff logic. This additional authentication traffic eventually brought AAD to its knees.

They ran out of time to discuss this further during the Ignite session, but one feature that they will be introducing will be giving users the ability to failover Storage Accounts manually in the future. So in the case where recovery time objective (RTO) is more important than (RPO) the user will have the ability to recover their asynchronously replicated geo-redundant storage in an alternate data center should Microsoft experience another extended outage in the future.

Until that time, you will have to rely on other replication solutions such as SIOS DataKeeper Azure Site Recovery, or application specific replication solutions which give you the ability to replicate data across regions and put the ability to enact your disaster recovery plan in your control.

 

 

Azure Outage Post-Mortem Part 3