Protecting Business Critical Apps By @DaveBerm | @CloudExpo [#Cloud] — Gartner predicts that the bulk of new IT spending by 2016 will be for cloud platforms and applications and that nearly half of large enterprises will have cloud deployments by the end of 2017. The benefits of the cloud may be clear for applications that can tolerate brief periods of downtime, but for critical applications like SQL Server, Oracle and SAP, companies need a strategy for HA and DR protection. While traditional SAN-based clusters are not possible in these environments, SANless clusters can provide an easy, cost-efficient alternative.
Read more at http://www.sys-con.com/node/3334102/blog#
Attend my session at Cloud-Expo on June 11th at the Javits Center in NYC – http://www.cloudcomputingexpo.com/event/session/2854
Windows Server has a new UserVoice page: http://windowsserver.uservoice.com/forums/295047-general-feedback with subsections:
This is where YOU get to provide Microsoft with your feedback directly.
Hi All – I wanted to let you know about a great free event that Microsoft and the MVPs are putting on, May 14th & 15th. Join Microsoft MVPs from the Americas’ region as they share their knowledge and real-world expertise during a free event, the MVP Virtual Conference.
The MVP Virtual Conference will showcase 95 sessions of content for IT Pros, Developers and Consumer experts designed to help you navigate life in a mobile-first, cloud-first world. Microsoft’s Corporate Vice President of Developer Platform, Steve Guggenheimer, will be on hand to deliver the opening Key Note Address.
Why attend MVP V-Conf? The conference will have 5 tracks, IT Pro English, Dev English, Consumer English, Portuguese mixed sessions & Spanish mixed sessions, there is something for everyone! Learn from the best and brightest MVPs in the tech world today and develop some great skills!
Be sure to register quickly to hold your spot and tell your friends & colleagues.
The conference will be widely covered on social media, you can join the conversation by following @MVPAward and using the hashtag #MVPvConf.
Register now and feel the power of community!
In case you missed my webinar yesterday, you can view the recording here. In 30 minutes I give an overview to some of the most exciting availability features being worked on for the next version of Windows Server due to ship sometime in 2016. Cloud Witness, Storage Replica and Rolling Cluster OS Updates are just three of the new features being release with v.Next.
If you set up a multisite cluster (nodes in different subnets), you will find that by default the cluster enables RegisterAllProvidersIP cluster resource for its network name. This results in two entries in DNS for the SQL Cluster name resource, one for each cluster IP address. If you use the optional MultiSubnetFailover=True parameter in the connection string, clients will try both IP addresses simultaneously and connect to the first server that responds. For SQL Server Management Studio you add that setting under the additional Connections Parameters.
There was an interesting discussion happening today in the Twitterverse. Basically, someone asked the question “Has anyone set up a SQL Server AlwaysOn Failover Cluster Instance in Azure?” The ensuing conversation involved some well respect SQL Server experts which led to the following question, “Why would you want to build a SQL Server AlwaysOn Failover Cluster instance in the cloud?”
That question could be interpreted in two ways: “Why do you need High Availability in the Cloud” or “Why wouldn’t you use AlwaysOn Availability Groups instead of Failover Cluster Instances?”
Let’s address each question one at a time.
Question 1 – Why do you need High Availability in the Azure Cloud?
- You might think that just because you host your SQL Server instance in Azure, that you are covered by their 99.95% uptime SLA. If you think that, you would be wrong. In order to take advantage of the 99.95% SLA you have to have at least two instances of SQL running in an Availability Set. With a single instance of SQL running you can definitely expect that there will minimally be downtime during maintenance periods, but you are also susceptible to unplanned failures.
- Two instances of SQL Server cannot generally be load balanced, so you have to implement some sort of mechanism to keep the servers in sync and to ensure that if there is a problem with one of the servers, the other server will be able to continue to service the requests. High Availability solutions like AlwaysOn Availability Groups, AlwaysOn Failover Cluster Instances and even the deprecated Database Mirroring can provide high availability for SQL Server in that scenario. Other solutions like log shipping and transactional replication may be able to help keep data synchronized between servers, but they are not typically considered high availability solutions and will not ensure the availability of your SQL Server.
- Microsoft does occasionally need to perform maintenance on Azure that could bring down an entire Upgrade Domain and all the instances running in that Upgrade Domain. You don’t have any say on when this will happen, so you need to have a mechanism in place to ensure that if they do have to bring down your primary SQL Server instance, you can expect that your secondary SQL Server instance will take over the workload without missing a beat. All of the high availability solutions mentioned above can ensure that you will continue to run in the event that Microsoft is doing maintenance on the Upgrade Domain of your primary server. Microsoft will only do maintenance on a single Upgrade Domain at a time, ensuring that your secondary server will still be online assuming you put the both in the same Availability Set.
- What do you do if YOU want to performance maintenance on your production SQL Server? Maybe you want to install a Service Pack or other hotfix? Without a secondary server to fail over to, you will have to schedule planned downtime. One of the primary benefits of any high availability solution is the ability to do rolling upgrades, minimizing the impact of planned downtime.
Question 2 – Why wouldn’t you use AlwaysOn Availability Groups instead of Failover Cluster Instances?
- Save Money! SQL Server AlwaysOn Availability Groups requires Enterprise Edition of SQL Server. Why not save money and deploy SQL Server Standard Edition and build a simple 2-node Failover Cluster Instance? Unless you need Enterprise Edition for some other reason, this is a no brainer.
- Protect the ENTIRE SQL Server instance. AlwaysOn Availability Groups only protects user defined databases; you cannot protect the System and MSDB databases. If you build a Failover Cluster Instance instead, you are protecting the ENTIRE instance, including the System and MSDB databases.
- Ease Administration. In Azure, you are limited to just on client listener. This limits you to just one Availability Group. In contrast, with a Failover Cluster Instance one client listener is all you need, so there is no limitation.
- Worker Thread Exhaustion. With AlwaysOn AG you have to keep an eye on the available worker threads. The available worker threads limit the number of databases you can protect with AlwaysOn AG. In contrast, AlwaysOn Failover Clustering with DataKeeper block level replication does not consume more resources for each database you add, meaning you can scale to protect hundreds of databases without the additional overhead associated with AlwaysOn AG.
- Distribute Transaction Support. AlwaysOn AG does not support distributed transactions (DTC), so if your application requires DTC support you are going to have to look at an AlwaysOn Failover Cluster Instance instead.
- Support of Other Replication Technologies. If you plan on setting up Peer to Peer replication between two databases protected by AlwaysOn AG you can forget about it. In fact, there are many restrictions you have to be aware of once you deploy AlwaysOn Availability Groups. AlwaysOn FCI’s do not have any of those restrictions.
Knowing what you know above, shouldn’t the question really be “Why would I want to implement AlwaysOn AG in the Cloud when I can have a much more robust and inexpensive solution building an AlwaysOn Failover Cluster instance?”
If you are interested in building an AlwaysOn Failover Cluster Instance in Azure, check out my blog post Step-by-Step: How to configure a SQL Server Failover Cluster Instance (FCI) in Microsoft Azure IaaS #SQLServer #Azure #SANLess
You can also check out the only Azure Certified HA solution in the Azure Marketplace at http://azure.microsoft.com/en-us/marketplace/partners/sios-datakeeper/sios-datakeeper-8-bring-your-own-license/
In case you missed it, I held this in depth webinar on cluster quorums. In 30 minutes I go over everything you need to know about quorums, from node majority through Cloud Witness and everything in between. If you have additional questions about quorums post them as a comment on this article and I will be glad to help.