Configuring a SQL Server failover cluster instance that uses Storage Spaces Direct

Microsoft SQL Server Always On Failover Cluster Instances (FCI) let you run a single SQL Server instance across multiple Windows Server Failover Cluster (WSFC) nodes. At any point in time, one of the cluster nodes actively hosts the SQL instance. In the event of a failure, WSFC automatically transfers ownership of the instance's resources to another node.

SQL Server FCI requires data to be located on shared storage so that it can be accessed across all WSFC nodes. This guide describes how you can deploy a SQL Server 2019 failover cluster instance that uses Storage Spaces Direct (S2D) for shared storage. S2D provides a software-based virtual SAN that can use Compute Engine VM data disks to store the SQL database.

The following diagram illustrates the deployment:

Implementing a hyper-converged architecture, the VM instances node-1 and node-2 serve as WSFC nodes and also host the shared storage. A third VM instance, witness, is used to achieve a quorum in a failover scenario. The three VM instances are distributed over three zones and share a common subnet.

Clients communicate with the SQL Server instance over an internal TCP load balancer. This load balancer uses the Windows Server Failover Clustering agent to determine which WSFC node is currently hosting the SQL instance and routes traffic to that instance.

The article assumes that you have already deployed Active Directory on Google Cloud and that you have basic knowledge of SQL Server, Active Directory, and Compute Engine.

Objectives

• Deploy a WSFC comprising two SQL Server VM instances and a third VM instance that acts as a file share witness.
• Deploy a SQL Server FCI on the WSFC.
• Verify that the cluster is working by simulating a failover.

Costs

This tutorial uses billable components of Google Cloud, including:

• Compute Engine
• Cloud Load Balancing

Use the pricing calculator to generate a cost estimate based on your projected usage.

Before you begin

To complete this guide, you need the following:

• An Active Directory domain with at least one domain controller. You can create an Active Directory domain by using Managed Microsoft AD. Alternatively, you can deploy a custom Active Directory environment on Compute Engine and set up a private DNS forwarding zone that forwards DNS queries to your domain controllers.
• An Active Directory user that has permission to join computers to the domain and can log in by using RDP. If you're using Managed Microsoft AD, you can use the setupadmin user.
• A Google Cloud project and VPC with connectivity to your Active Directory domain controllers.
• A subnet to use for the WSFC VM instances.

To complete the guide, you also need a GCP project:

1. Sign in to your Google Cloud account. If you're new to Google Cloud, create an account to evaluate how our products perform in real-world scenarios. New customers also get $300 in free credits to run, test, and deploy workloads.

2. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

   Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

   Go to project selector

3. Make sure that billing is enabled for your Cloud project. Learn how to check if billing is enabled on a project.

4. In the Google Cloud console, on the project selector page, select or create a Google Cloud project.

   Note: If you don't plan to keep the resources that you create in this procedure, create a project instead of selecting an existing project. After you finish these steps, you can delete the project, removing all resources associated with the project.

   Go to project selector

5. Make sure that billing is enabled for your Cloud project. Learn how to check if billing is enabled on a project.

When you finish this tutorial, you can avoid continued billing by deleting the resources you created. For more information, see Cleaning up.

Preparing the project and network

To prepare your Google Cloud project and VPC for the deployment of SQL Server FCI, do the following:

1. In the Google Cloud console, open Cloud Shell by clicking the Activate Cloud Shell button.

   Go to the Google Cloud console

2. Initialize the following variables:

   VPC_NAME=VPC_NAME
   SUBNET_NAME=SUBNET_NAME
   

   Where:

   • VPC_NAME: name of your VPC
   • SUBNET_NAME: name of your subnet

3. Set your default project ID:

   gcloud config set project PROJECT_ID
   

   Replace PROJECT_ID with the ID of your Google Cloud project.

4. Set your default region:

   gcloud config set compute/region REGION
   

   Replace REGION with the ID of the region you want to deploy in.

Create firewall rules

To allow clients to connect to SQL Server, allow communication between the WSFC nodes, and to enable the load balancer to perform health checks, you need to create several firewall rules. To simplify the creation of these firewall rules, you use network tags:

• The 2 WSFC nodes are annotated with the wsfc-node tag.
• All servers (including the witness) are annotated with the wsfc tag.

Create firewall rules that use these network tags:

1. Return to your existing Cloud Shell session.

2. Create firewall rules for the WSFC nodes:

   SUBNET_CIDR=$(gcloud compute networks subnets describe $SUBNET_NAME --format=value\('ipCidrRange'\))
   
   gcloud compute firewall-rules create allow-all-between-wsfc-nodes \
     --direction=INGRESS \
     --action=allow \
     --rules=tcp,udp,icmp \
     --enable-logging \
     --source-tags=wsfc \
     --target-tags=wsfc \
     --network=$VPC_NAME \
     --priority 10000
   
   gcloud compute firewall-rules create allow-sql-to-wsfc-nodes \
     --direction=INGRESS \
     --action=allow \
     --rules=tcp:1433 \
     --enable-logging \
     --source-ranges=$SUBNET_CIDR \
     --target-tags=wsfc-node \
     --network=$VPC_NAME \
     --priority 10000
   

3. Create a firewall rule that allows health checks from the IP ranges of the Google Cloud probers:

   gcloud compute firewall-rules create allow-health-check-to-wsfc-nodes \
     --direction=INGRESS \
     --action=allow \
     --rules=tcp \
     --source-ranges=130.211.0.0/22,35.191.0.0/16 \
     --target-tags=wsfc-node \
     --network=$VPC_NAME \
     --priority 10000
   

Note: Depending on how you've deployed Active Directory, you might need to create additional firewall rules to allow servers to join the domain. See Accessing Managed Microsoft AD from within your VPC for further details.

Create VM instances

You now deploy two VM instances for the failover cluster. At any point in time, only one of these VMs serves as the active FCI node while the other node serves as the failover node. The two VM instances must:

• be located in the same region so that they can accessed by an internal TCP load balancer.
• have Windows Server Failover Clustering and SQL Server installed.
• have Compute Engine WSFC support enabled.

You use a SQL Server premium image which has SQL Server 2019 preinstalled.

Note: If you plan to bring your own licenses for SQL Server by using the license mobility program, select Windows Server base images for these nodes and install SQL Server using your own product keys.

To provide a tie-breaking vote and achieve a quorum for the failover scenario, you deploy a third VM that serves as a file share witness.

1. Return to your existing Cloud Shell session.

2. Create a specialize script for the WSFC nodes. The script installs the necessary Windows feature and creates firewall rules for WSFC and SQL Server:

   cat << "EOF" > specialize-node.ps1
   
   $ErrorActionPreference = "stop"
   
   # Install required Windows features
   Install-WindowsFeature Failover-Clustering -IncludeManagementTools
   Install-WindowsFeature RSAT-AD-PowerShell
   
   # Open firewall for WSFC
   netsh advfirewall firewall add rule name="Allow SQL Server health check" dir=in action=allow protocol=TCP localport=59997
   
   # Open firewall for SQL Server
   netsh advfirewall firewall add rule name="Allow SQL Server" dir=in action=allow protocol=TCP localport=1433
   
   EOF
   

3. Create the VM instances. On the two VMs that serve as S2D and WSFC nodes, attach additional data disks and enable the Windows Server Failover Clustering by setting the metadata key enable-wsfc to true:

   REGION=$(gcloud config get-value compute/region)
   PD_SIZE=50
   MACHINE_TYPE=n2-standard-8
   
   gcloud compute instances create node-1 \
     --zone $REGION-a \
     --machine-type $MACHINE_TYPE \
     --subnet $SUBNET_NAME \
     --image-family sql-ent-2019-win-2019 \
     --image-project windows-sql-cloud \
     --tags wsfc,wsfc-node \
     --boot-disk-size 50 \
     --boot-disk-type pd-ssd \
     --boot-disk-device-name "node-1" \
     --create-disk=name=node-1-datadisk-1,size=$PD_SIZE,type=pd-ssd,auto-delete=no \
     --create-disk=name=node-1-datadisk-2,size=$PD_SIZE,type=pd-ssd,auto-delete=no \
     --create-disk=name=node-1-datadisk-3,size=$PD_SIZE,type=pd-ssd,auto-delete=no \
     --create-disk=name=node-1-datadisk-4,size=$PD_SIZE,type=pd-ssd,auto-delete=no \
     --metadata enable-wsfc=true \
     --metadata-from-file=sysprep-specialize-script-ps1=specialize-node.ps1
   
   gcloud compute instances create node-2 \
     --zone $REGION-b \
     --machine-type $MACHINE_TYPE \
     --subnet $SUBNET_NAME \
     --image-family sql-ent-2019-win-2019 \
     --image-project windows-sql-cloud \
     --tags wsfc,wsfc-node \
     --boot-disk-size 50 \
     --boot-disk-type pd-ssd \
     --boot-disk-device-name "node-2" \
     --create-disk=name=node-2-datadisk-1,size=$PD_SIZE,type=pd-ssd,auto-delete=no \
     --create-disk=name=node-2-datadisk-2,size=$PD_SIZE,type=pd-ssd,auto-delete=no \
     --create-disk=name=node-2-datadisk-3,size=$PD_SIZE,type=pd-ssd,auto-delete=no \
     --create-disk=name=node-2-datadisk-4,size=$PD_SIZE,type=pd-ssd,auto-delete=no \
     --metadata enable-wsfc=true \
     --metadata-from-file=sysprep-specialize-script-ps1=specialize-node.ps1
   
   gcloud compute instances create "witness" \
     --zone $REGION-c \
     --machine-type n2-standard-2 \
     --subnet $SUBNET_NAME \
     --image-family=windows-2019 \
     --image-project=windows-cloud \
     --tags wsfc \
     --boot-disk-size 50 \
     --boot-disk-type pd-ssd \
     --metadata sysprep-specialize-script-ps1="add-windowsfeature FS-FileServer"
   

   Note: Depending on your performance requirements, consider using a machine type larger than n2-standard-8 for the WSFC nodes.
   Note: For the purpose of this tutorial, and to fit within the default regional SSD persistent disk quota, the size of the disks attached to each VM is smaller than it would be in a production environment. For better performance and to accommodate a larger database, you would increase the size of each disk. For more information about choosing S2D drives, refer to the S2D documentation.

4. To join the 3 VM instances to Active Directory, do the following for each of the 3 VM instances:

   1. Monitor the initialization process of the VM by viewing its serial port output:

      gcloud compute instances tail-serial-port-output NAME
      

      Replace NAME with the name of the VM instance.

      Wait about 3 minutes until you see the output Instance setup finished, then press Ctrl+C. At this point, the VM instance is ready to be used.

   2. Create a username and password for the VM instance

   3. Connect to the VM by using Remote Desktop and log in using the username and password created in the previous step.

   4. Right-click the Start button (or press Win+X) and click Windows PowerShell (Admin).

   5. Confirm the elevation prompt by clicking Yes.

   6. Join the computer to your Active Directory domain and restart:

      Add-Computer -Domain DOMAIN -Restart
      

      Replace DOMAIN with the DNS name of your Active Directory domain.

      Wait for approximately 1 minute for the restart to complete.

Reserve cluster IP addresses

You now reserve two static IP addresses in your VPC. One IP address is used as the WSFC cluster IP address, the other is used by the internal load balancer.

1. Reserve a static IP for the internal load balancer and capture the address in a new environment variable named LOADBALANCER_ADDRESS:

   gcloud compute addresses create wsfc \
     --subnet $SUBNET_NAME \
     --region $(gcloud config get-value compute/region)
   
   LOADBALANCER_ADDRESS=$(gcloud compute addresses describe wsfc \
     --region $(gcloud config get-value compute/region) \
     --format=value\(address\)) && \
   echo "Load Balancer IP: $LOADBALANCER_ADDRESS"
   

   Note the IP address, you need it later.

2. Reserve another static IP address that you use as cluster IP:

   gcloud compute addresses create wsfc-cluster \
     --subnet $SUBNET_NAME \
     --region $(gcloud config get-value compute/region) && \
   CLUSTER_ADDRESS=$(gcloud compute addresses describe wsfc-cluster \
       --region $(gcloud config get-value compute/region) \
       --format=value\(address\)) && \
   echo "Cluster IP: $CLUSTER_ADDRESS"
   

   Note the IP address, you need it later.

Your project and VPC are now ready for the deployment of the WSFC and SQL Server.

Create a witness file share

To prepare witness to serve as file share witness, create a file share and grant yourself and the two WSFC nodes access to the file share:

1. Connect to witness by using Remote Desktop. Log in with your domain user account.
2. Right-click the Start button (or press Win+X) and click Windows PowerShell (Admin).
3. Confirm the elevation prompt by clicking Yes.

4. Create the witness folder and share the folder:

   New-Item "C:\QWitness" –type directory
   
   icacls C:\QWitness\ /grant 'node-1$:(OI)(CI)(M)'
   icacls C:\QWitness\ /grant 'node-2$:(OI)(CI)(M)'
   
   New-SmbShare `
     -Name QWitness `
     -Path "C:\QWitness" `
     -Description "SQL File Share Witness" `
     -FullAccess  $env:username,node-1$,node-2$
   

Deploying the failover cluster

You now use the VM instances to deploy a WSFC and SQL Server.

Deploy WSFC

You are now ready to create the failover cluster:

1. Connect to node-1 by using Remote Desktop. Log in with your domain user account.
2. Right-click the Start button (or press Win+X) and click Windows PowerShell (Admin).
3. Confirm the elevation prompt by clicking Yes.

4. Create a new cluster:

   New-Cluster `
     -Name windows-fci `
     -Node node-1,node-2 `
     -NoStorage `
     -StaticAddress CLUSTER_ADDRESS
   

   Replace CLUSTER_ADDRESS with the cluster IP address that you created earlier.

5. Return to the PowerShell session on witness and grant the virtual computer object of the cluster permission to access the file share:

   icacls C:\QWitness\ /grant 'windows-fci$:(OI)(CI)(M)'
   Grant-SmbShareAccess `
     -Name QWitness `
     -AccountName 'windows-fci$' `
     -AccessRight Full `
     -Force
   

6. Return to the PowerShell session on node-1 and configure the cluster to use the file share on witness as a cluster quorum:

   Set-ClusterQuorum -FileShareWitness \\witness\QWitness
   

7. Verify that the cluster was created successfully:

   Test-Cluster
   

   You might see some warnings that can be safely ignored:

   WARNING: System Configuration - Validate All Drivers Signed: The test reported some warnings..
   WARNING: Network - Validate Network Communication: The test reported some warnings..
   WARNING:
   Test Result:
   HadUnselectedTests, ClusterConditionallyApproved
   Testing has completed for the tests you selected. You should review the warnings in the Report.  A cluster solution is
   supported by Microsoft only if you run all cluster validation tests, and all tests succeed (with or without warnings).
   

   You can also launch the Failover Cluster Manager MMC snap-in to review the cluster's health by running cluadmin.msc.

8. If you're using Managed AD, add the computer account used by WSFC to the Cloud Service Domain Join Accounts group so that it can join computers to the domain:

   Add-ADGroupMember `
     -Identity "Cloud Service Domain Join Accounts" `
     -Members windows-fci$
   

Enabling Storage Spaces Direct

You now enable S2D and create a cluster shared volume which combines the three persistent disks that you created earlier:

1. Return to the PowerShell session on node-1.

2. Enable S2D:

   Enable-ClusterStorageSpacesDirect
   

   Optionally, if you want better disk performance, you can add SCSI local SSDs to your S2D nodes in addition to standard SSD persistent disks. The local SSDs can serve as the S2D caching layer. Make the number of capacity drives (SSD persistent disks in our case) a multiple of the number of local SSDs. Run the following command instead for enabling S2D with caching:

   Enable-ClusterStorageSpacesDirect -CacheDeviceModel "EphemeralDisk"
   

   Accept the default when prompted to confirm. You might see some warnings that can be safely ignored:

   WARNING: 2021/04/08-13:12:26.159 Node node-1: No disks found to be used for cache
   WARNING: 2021/04/08-13:12:26.159 Node node-2: No disks found to be used for cache
   

3. Optionally, set the Cluster Shared Volume (CSV) in-memory cache to 2048 MB for better read throughput:

   (Get-Cluster).BlockCacheSize = 2048
   

4. Create a new volume that uses the cluster shared volume versions of ReFS and a 64 KB cluster size:

   New-Volume `
     -StoragePoolFriendlyName S2D* `
     -FriendlyName FciVolume `
     -FileSystem CSVFS_ReFS `
     -UseMaximumSize `
     -AllocationUnitSize 65536
   

5. Open the Failover Cluster Manager MMC snap-in:

   cluadmin.msc
   

6. In the left window pane, navigate to Failover Cluster Manager > windows-fci > Storage > Disks.

7. Right-click Cluster Virtual Disk (FciVolume) and select Remove From Cluster Shared Volumes.

8. Select Cluster Virtual Disk (FciVolume).

9. In the Volumes tab at the bottom, right-lick the volume and select Change drive letter.

10. Select the drive letter D and click OK.

Testing storage pool failover

Optionally, you can now test whether the storage pool failover works properly:

1. Connect to node-2 by using Remote Desktop. Log in with your domain user account.
2. Right-click the Start button (or press Win+X) and select Run
3. Enter cluadmin.msc and select OK.

4. In the left window pane, navigate to Failover Cluster Manager > windows-fci > Storage > Pools.

   You should see a pool named Cluster Pool 1 with Owner node set to node-1.

5. Return to Cloud Shell and reset node-1 VM to simulate a failover:

   gcloud compute instances reset node-1 --zone $REGION-a
   

6. Return to the Failover Cluster Manager on node-2.

7. Observe the status of the storage pool by repeatedly pressing F5 to refresh the view.

   After about 30 seconds, the owner node should automatically switch to node-2.

Remove the default SQL Server installation

You now remove the default SQL Server installation from the two nodes and replace it with a new FCI configuration.

For each of the two WSFC nodes, node-1 and node-2, perform the following steps:

1. Right-click the Start button (or press Win+X) and click Windows PowerShell (Admin).
2. Confirm the elevation prompt by clicking Yes.

3. Remove the default SQL Server instance:

   C:\sql_server_install\Setup.exe /Action=Uninstall /FEATURES=SQL,AS,IS,RS /INSTANCENAME=MSSQLSERVER /Q
   

4. Restart the computer:

   Restart-Computer
   

5. Wait for approximately 1 minute for the restart to complete.

Install SQL Server FCI

Before you install the new FCI configuration, verify that the node-1 is the active node in the cluster:

1. Reconnect to node-1 by using Remote Desktop and log in using your domain user.
2. Right-click the Start button (or press Win+X) and select Run
3. Enter cluadmin.msc and select OK.

4. In the left window pane, navigate to Failover Cluster Manager > windows-fci.

   Verify that the current host server is set to node-1.

   If the current host server is set to node-2, right-click windows-fci in the left window pane and select More actions > Move core cluster resources > Select node… > node-1 and click OK.

5. In the left window pane, navigate to Failover Cluster Manager > windows-fci > Storage > Pools.

   Verify that the owner node of Cluster Pool 1 is set to node-1.

   If the owner node is set to node-2, right-click the pool, select Move > Select Node > node-1 and click OK.

You now create a new SQL Server failover cluster installation on node-1:

1. Right-click the Start button (or press Win+X) and click Windows PowerShell (Admin).
2. Confirm the elevation prompt by clicking Yes.

3. Create a domain user account for SQL server and the SQL agent and assign a password:

   $Credential = Get-Credential -UserName sql_server -Message 'Enter password'
   New-ADUser `
     -Name "sql_server" `
     -Description "SQL Agent and SQL Admin account." `
     -AccountPassword $Credential.Password `
     -Enabled $true -PasswordNeverExpires $true
   

   Note: If you use Managed AD, append -Path "OU=Cloud,DC=example,DC=org" to the command to create the user in the Cloud OU.

4. Start the SQL Server setup:

   & c:\sql_server_install\setup.exe
   

5. In the menu on the left, select Installation.

6. Select New SQL Server failover cluster installation

7. On the Microsoft Update page, select Next to start the installation.

8. On the Install Failover Cluster Rules page, you see a Warning MSCS cluster verification warnings and Windows firewall. You can ignore these warnings and select Next.

9. On the Product Key page, keep the defaults and select Next.

10. On the License Terms page, review the terms and, if you accept, select Next.

11. On the Feature Selection page, select Database Engine Services and select Next.

12. On the Instance Configuration page, enter sql as network name and select Next.

13. On the Cluster Resource Group page, keep the defaults and select Next.

14. On the Cluster Disk Selection page, select Cluster Virtual Disk (FciVolume) and select Next.

15. On the Cluster Network Configuration page, configure the following settings, then select Next:

    • DHCP: clear
    • IP address: enter the IP address of the internal load balancer.

16. On the Server configuration page, configure the following settings for both SQL Server Agent and SQL Server Database Engine:

    • Account name: DOMAIN\sql_server where DOMAIN is the NetBIOS name of your Active Directory domain
    • Password: Enter the password that you created earlier

17. Select the Collation tab and select the collation that you want to use. Then click Next.

18. On the Database Engine Configuration page, select Add current user to designate the current user as SQL Server administrator. Then select Next.

19. On the Ready to Install page, review the settings, then select Install.

20. After the installation completes, select Close.

Now add node-2 to the SQL Server failover cluster:

1. Connect to node-2 by using Remote Desktop and log in using your domain user.
2. Right-click the Start button (or press Win+X) and click Windows PowerShell (Admin).
3. Confirm the elevation prompt by clicking Yes.

4. Start the SQL Server setup:

   & c:\sql_server_install\setup.exe
   

5. In the menu on the left, select Installation.

6. Select Add node to a SQL Server failover cluster.

7. Follow the instructions of the installation wizard and accept the default settings until you reach the page Service Accounts.

8. On the Service Accounts page, enter the password that you created earlier for both SQL Server Agent and SQL Server Database Engine. Then select Next.

9. On the Ready to Install page, review the settings, then select Install.

10. After the installation completes, select Close.

Configure health checks

As a final step, configure the cluster to expose a health check endpoint that can be used by an internal load balancer:

1. Return to the PowerShell session on node-2

2. Initialize a variable with the IP address of the load balancer.

   $LoadBalancerIP = 'IP_ADDRESS'
   

   Replace IP_ADDRESS with the IP address of the wsfc address that you reserved earlier.

3. Configure the Failover Cluster to respond to the health check service:

   $SqlGroup = Get-ClusterGroup |
     Where-Object {$_.Name.StartsWith("SQL Server")}
   $SqlIpAddress = Get-ClusterResource |
     Where-Object {$_.Name.StartsWith("SQL IP Address")}
   
   $SqlIpAddress | Set-ClusterParameter -Multiple @{
    'Address'=$LoadBalancerIP;
    'ProbePort'= 59997;
    'SubnetMask'='255.255.255.255';
    'Network'= (Get-ClusterNetwork).Name;
    'EnableDhcp'=0; }
   

4. Restart the cluster resource:

   $SqlIpAddress | Stop-ClusterResource
   $SqlIpAddress | Start-ClusterResource
   

5. Restart the cluster group:

   $SqlGroup | Stop-ClusterGroup
   $SqlGroup | Start-ClusterGroup
   

Create an internal load balancer

To provide a single endpoint for SQL Server clients, you now deploy an internal load balancer. The load balancer uses a health check which ensures that traffic is directed to the active node of the WSFC.

1. Return to your existing Cloud Shell session.

2. Create two unmanaged instance groups, one per zone, and add the two nodes to the groups:

   gcloud compute instance-groups unmanaged create wsfc-group-1 --zone $REGION-a
   gcloud compute instance-groups unmanaged add-instances wsfc-group-1 --zone $REGION-a \
     --instances node-1
   
   gcloud compute instance-groups unmanaged create wsfc-group-2 --zone $REGION-b
   gcloud compute instance-groups unmanaged add-instances wsfc-group-2 --zone $REGION-b \
     --instances node-2
   

3. Create a health check that the load balancer can use to determine which is the active node.

   gcloud compute health-checks create tcp wsfc-healthcheck \
     --check-interval="2s" \
     --healthy-threshold=1 \
     --unhealthy-threshold=2 \
     --port=59997 \
     --timeout="1s"
   

   The health check probes port 59997, which is the port you previously configured as ProbePort for the WSFC cluster IP address.

4. Create a backend service and add the two instance groups:

   gcloud compute backend-services create wsfc-backend \
     --load-balancing-scheme internal \
     --region $(gcloud config get-value compute/region) \
     --health-checks wsfc-healthcheck \
     --protocol tcp
   
   gcloud compute backend-services add-backend wsfc-backend \
     --instance-group wsfc-group-1 \
     --instance-group-zone $REGION-a \
     --region $REGION
   
   gcloud compute backend-services add-backend wsfc-backend \
     --instance-group wsfc-group-2 \
     --instance-group-zone $REGION-b \
     --region $REGION
   

5. Create the internal load balancer:

   gcloud compute forwarding-rules create wsfc-sql \
     --load-balancing-scheme internal \
     --address $LOADBALANCER_ADDRESS \
     --ports 1433 \
     --network $VPC_NAME \
     --subnet $SUBNET_NAME \
     --region $REGION \
     --backend-service wsfc-backend
   

Testing the failover cluster

You've completed the installation of the failover cluster, but you still have to test whether the cluster works correctly.

Prepare a client

Create a new VM instance which you can use to connect to the failover cluster:

1. Return to your existing Cloud Shell session.

2. Create a new VM instance:

   gcloud compute instances create sqlclient \
     --zone $REGION-a \
     --machine-type n2-standard-2 \
     --subnet $SUBNET_NAME \
     --image-family sql-ent-2019-win-2019 \
     --image-project windows-sql-cloud \
     --boot-disk-size 50 \
     --boot-disk-type pd-ssd
   

3. Monitor the initialization process of the VM by viewing its serial port output:

   gcloud compute instances tail-serial-port-output sqlclient
   

   Wait about 3 minutes until you see the output Instance setup finished, then press Ctrl+C. At this point, the VM instance is ready to be used.

4. Create a username and password for the VM instance

5. Connect to the VM by using Remote Desktop and log in using the username and password created in the previous step.

6. Right-click the Start button (or press Win+X) and click Windows PowerShell (Admin).

7. Confirm the elevation prompt by clicking Yes.

8. Join the computer to your Active Directory domain:

   Add-Computer -Domain DOMAIN
   

   Replace DOMAIN with the DNS name of your Active Directory domain.

9. Restart the computer:

   Restart-Computer
   

   Wait for approximately 1 minute for the restart to complete.

Run the test

Use the sqlclient VM to test that you can connect to the failover cluster and to verify that the failover works correctly:

1. Connect to sqlclient by using Remote Desktop and log in using your domain user.
2. Right-click the Start button (or press Win+X) and click Windows PowerShell.

3. Connect to SQL Server cluster by using its network name sql and query the dm_os_cluster_nodes table:

   & "$env:ProgramFiles\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn\SQLCMD.EXE" `
      -S sql -E -Q "SELECT * FROM sys.dm_os_cluster_nodes"
   

   The output should look like this:

   NodeName                       status      status_description is_current_owner
   ------------------------------ ----------- ------------------ ----------------
   NODE-1                                   0 up                                1
   NODE-2                                   0 up                                0
   
   (2 rows affected)
   

   Notice that node-1 is the current owner of the SQL Server failover cluster resource.

4. Return to Cloud Shell and bring down the node-1 VM to test the failover scenario.

   gcloud compute instances stop node-1 --zone $REGION-a
   

5. Repeat the query:

   & "$env:ProgramFiles\Microsoft SQL Server\Client SDK\ODBC\170\Tools\Binn\SQLCMD.EXE" `
      -S sql -E -Q "SELECT * FROM sys.dm_os_cluster_nodes"
   

   The output should now look like this:

   NodeName                       status      status_description is_current_owner
   ------------------------------ ----------- ------------------ ----------------
   NODE-1                                   1 down                              0
   NODE-2                                   0 up                                1
   
   (2 rows affected)
   

   Notice that despite the loss of node-1, the query succeeds, and shows that node-2 is now the current owner of the failover cluster.

Limitations

• Storage Spaces Direct(S2D) is only supported for Windows Server 2016 and above.
• With S2D, each disk only contains a partial view of the overall data. So taking a snapshot of a persistent disk won't be enough to back up your data. Use native SQL backup instead.

Clean up

After you finish the tutorial, you can clean up the resources that you created so that they stop using quota and incurring charges. The following sections describe how to delete or turn off these resources.

Deleting the project

The easiest way to eliminate billing is to delete the project that you created for the tutorial.

To delete the project:

Caution: Deleting a project has the following effects:

• Everything in the project is deleted. If you used an existing project for this tutorial, when you delete it, you also delete any other work you've done in the project.
• Custom project IDs are lost. When you created this project, you might have created a custom project ID that you want to use in the future. To preserve the URLs that use the project ID, such as an appspot.com URL, delete selected resources inside the project instead of deleting the whole project.

If you plan to explore multiple tutorials and quickstarts, reusing projects can help you avoid exceeding project quota limits.

1. In the Cloud console, go to the Manage resources page.

   Go to Manage resources

2. In the project list, select the project that you want to delete, and then click Delete.
3. In the dialog, type the project ID, and then click Shut down to delete the project.

What's next

• Learn how you can configure a SQL Server failover cluster instance that uses persistent disks in multi-writer mode.