I was the principal author of this SIOS whitepaper, which describes how to build a 2-node SQL Server cluster in Google Cloud Platform (GCP) spanning multiple zones. Today, I’ll explain how to extend this cluster by adding a third node in a different GCP region.

Assuming you’ve completed all the steps in the referenced documentation, here’s how to proceed:

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1. Create Subnet

Create a new subnet in the additional region.

gcloud compute networks subnets create wsfcnetsub1 \
    --network wsfcnet \
    --region us-west1 \
    --range 10.1.0.0/16

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2. Configure Firewall for Internal Communication

Open up firewall rules to allow internal communication on the new subnet.

gcloud compute firewall-rules create allow-all-subnet-10-1 \
    --network wsfcnet \
    --allow all \
    --source-ranges 10.1.0.0/16

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3. Verify Available Zones

Check which zones exist in the new region (e.g., us-west1).

gcloud compute zones list \
    --filter="region:(us-west1)" \
    --format="value(name)"

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4. Check VM Types Supporting Local SSD

Find the VM types that support local SSD in your target zone.

gcloud compute machine-types list \
    --zones us-west1-a \
    --filter="guestCpus>0 AND name:(n2 n2-highmem n2-highcpu c2 e2-custom e2-custom-memory e2-custom-cpu)" \
    --sort-by=guestCpus

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5. Create New VM Instance

Create the new VM in the chosen zone with appropriate settings.

gcloud compute instances create wsfc-3 \
 --zone us-west1-a \
 --machine-type n2-standard-2 \
 --image-project windows-cloud \
 --image-family windows-2016 \
 --scopes https://www.googleapis.com/auth/compute \
 --can-ip-forward \
 --private-network-ip 10.1.0.4 \
 --network wsfcnet \
 --subnet wsfcnetsub1 \
 --metadata enable-wsfc=true \
 --local-ssd interface=nvme \
 --create-disk=auto-delete=yes,boot=no,device-name=extradisk1,size=1,type=pd-standard

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6. Set Windows Password

Set a Windows password for accessing the new VM.

gcloud compute reset-windows-password wsfc-3 \
    --zone us-west1-a \
    --user david

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7. Configure Windows Networking

On wsfc-3, run these PowerShell commands to configure the network.

# Remove existing DHCP configuration
Remove-NetIPAddress -InterfaceAlias "Ethernet 2" -AddressFamily IPv4 -Confirm:$false
# Set static IP
New-NetIPAddress -InterfaceAlias "Ethernet 2" -IPAddress 10.1.0.4 -PrefixLength 16 -DefaultGateway 10.1.0.1
# Set DNS server
Set-DnsClientServerAddress -InterfaceAlias "Ethernet 2" -ServerAddresses 10.0.0.6

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8. Bring Extra Storage Online

Run these PowerShell commands to initialize and format the additional storage.

# Identify the new disk
$disks = Get-Disk | Where-Object IsOffline -Eq $false
$newDisk = $disks | Where-Object PartitionStyle -Eq 'RAW'
# Initialize and format new disk
Initialize-Disk -Number $newDisk.Number -PartitionStyle MBR
New-Partition -DiskNumber $newDisk.Number -UseMaximumSize -AssignDriveLetter | Format-Volume -FileSystem NTFS -NewFileSystemLabel "ExtraDisk"

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9. Ensure Local SSD Attaches on Startup

Use this script to format and mount the local SSD on startup. Call it AttachSSD.ps1 and save it here. C:\Scripts\AttachSSD.ps1

$diskNumber = 0
$driveLetter = "F"
# Check drive letter availability
if (Get-PSDrive -Name $driveLetter -ErrorAction SilentlyContinue) {
    exit
}
# Initialize and format if RAW
$disk = Get-Disk -Number $diskNumber -ErrorAction SilentlyContinue
while (-not $disk) {

    Start-Sleep -Seconds 5

    $disk = Get-Disk -Number $diskNumber -ErrorAction SilentlyContinue

}
if ($disk.PartitionStyle -eq 'RAW') {

    Initialize-Disk -Number $diskNumber -PartitionStyle GPT

}

$existingPartition = Get-Partition -DiskNumber $diskNumber -ErrorAction SilentlyContinue

if (-not $existingPartition) {

    $partition = New-Partition -DiskNumber $diskNumber -UseMaximumSize -AssignDriveLetter

    Format-Volume -DriveLetter $partition.DriveLetter -FileSystem NTFS -NewFileSystemLabel "LocalSSD"

    Set-Partition -DriveLetter $partition.DriveLetter -NewDriveLetter $driveLetter

}

Schedule Script to Run at Startup:

$taskName = "InitializeLocalSSD"
$scriptPath = "C:\Scripts\AttachSSD.ps1"
$action = New-ScheduledTaskAction -Execute "powershell.exe" -Argument "-NoProfile -ExecutionPolicy Bypass -File `"$scriptPath`""

$trigger = New-ScheduledTaskTrigger -AtStartup

$principal = New-ScheduledTaskPrincipal -UserId "SYSTEM" -LogonType ServiceAccount -RunLevel Highest

Register-ScheduledTask -TaskName $taskName -Action $action -Trigger $trigger -Principal $principal

10. Join the Domain

Join the new server to the domain.

$domain = "datakeeper.local"
$username = "administrator@datakeeper.local"

$password = "YourPassword!"

$securePassword = ConvertTo-SecureString $password -AsPlainText -Force

$credential = New-Object System.Management.Automation.PSCredential ($username, $securePassword)

Add-Computer -DomainName $domain -Credential $credential -Force

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11. Add a new mirror to the existing Datakeeper job

Follow the screenshots below to extend the existing DataKeeper job to the new server.

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12. Install Windows Failover Clustering and add to the cluster

Install clustering tools and add the node to the cluster.

Install-WindowsFeature -Name Failover-Clustering -IncludeManagementTools
Add-ClusterNode -Cluster fileserver.datakeeper.local -Name wsfc-3

Test-Cluster -Name fileserver.datakeeper.local

Note: Adding the node through the WSFC UI may be necessary if there’s a load balancer issue with the cluster name.

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13. Install SQL Server on the new cluster node

Run SQL Server setup and choose add node to existing cluster installation option. https://learn.microsoft.com/en-us/sql/sql-server/failover-clusters/install/add-or-remove-nodes-in-a-sql-server-failover-cluster-setup?view=sql-server-ver16

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14. Create New Load Balancer Rules

Configure load balancing to allow access across regions.

gcloud compute instance-groups unmanaged create wsfc-group-3 --zone=us-west1-a

gcloud compute instance-groups unmanaged add-instances wsfc-group-3 --instances wsfc-3 --zone us-west1-a

# Set environment variables
export REGION="us-west1"
export NETWORK="wsfcnet"
export SUBNET="wsfcnetsub1"
export LB_NAME="swfc-lbwest"
export HEALTH_CHECK_NAME="wsfc-hc-west"
export HEALTH_CHECK_PORT="59998"
export BACKEND_PORTS="1433"
export BACKEND_IP="10.1.0.9"
export BACKEND_RESPONSE="1"
export LB_INTERNAL_IP="10.1.0.9"

# Step 1: Create Health Check
gcloud compute health-checks create tcp $HEALTH_CHECK_NAME \
 --region=$REGION \
 --port=$HEALTH_CHECK_PORT \
 --check-interval=2s \
 --timeout=1s \
 --unhealthy-threshold=2 \
 --healthy-threshold=2

# Step 2: Create Backend Service
gcloud compute backend-services create $LB_NAME-backend \
 --load-balancing-scheme=INTERNAL \
 --protocol=TCP \
 --region=$REGION \
 --health-checks=$HEALTH_CHECK_NAME \
 --health-checks-region=$REGION

# Step 3: Add Backend Instance Group
gcloud compute backend-services add-backend $LB_NAME-backend \
 --instance-group=wsfc-group-3 \
 --instance-group-zone=us-west1-a \
 --region=$REGION

# Step 4: Create Frontend Configuration (Forwarding Rule)
gcloud compute forwarding-rules create $LB_NAME \
 --load-balancing-scheme=INTERNAL \
 --ports=$BACKEND_PORTS \
 --network=$NETWORK \
 --subnet=$SUBNET \
 --region=$REGION \
 --backend-service=$LB_NAME-backend \
 --ip-protocol=TCP \
 --address=$LB_INTERNAL_IP
 --allow-global-access

Update the original load balancing forwarding rule to allow global access

gcloud compute forwarding-rules update wsfc-lb --region=us-east1 --allow-global-access

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This completes the steps to extend your SQL Server cluster across multiple GCP regions. In the future I’ll probably write a single comprehensive how-to guide, but for now, let me know if you have any questions!