Embedded Files
Windows Server Failover Cluster
Number of Nodes
Number of Nodes
Each cluster uses the concept of a "quorum node set" to determine which nodes control the cluster.
In simple terms this means that we need an odd number of participants in any "quorum vote" to ensure that one quorum node set can win that vote.
In a cluster with an even number of nodes we can use a "witness" (a shared disk or a file share) to meet that requirement.
We can avoid this by using an odd number of voting nodes.
Note that we can control whether a node has a vote.
A four node cluster with only three voting nodes is possible, as is a three node cluster with two voting nodes and a witness.
Enable Failover Clustering
Enable Failover Clustering
You can install WSFC using...
Install-WindowsFeature -Name Failover-Clustering –IncludeManagementTools - restart
The server will reboot automatically after installation is completeAn alternate (older) syntax from Mark Broadbent...
Add-WindowsFeature failover-clustering -IncludeAllSubFeature -IncludeManagementTools
Validate Configuration
Validate Configuration
Test-Cluster -Node NODE1,NODE2,NODE3 -Include "Storage Spaces Direct", "Inventory", "Network", "System Configuration"
Create Cluster
Create Cluster
New-Cluster -Name AGCLUSTER -Node NODE1,NODE2,NODE3 -StaticAddress 10.10.10.50 -NoStorage
Validate Configuration
This configuration is stored primarily in the cluster database on the nodes themselves.Validate Configuration
Get-Cluster
Name----AGCLUSTER
Get-ClusterNode
Name State Type---- ----- ----NODE1 Up NodeNODE2 Up NodeNODE3 Up Node
NOTE: Output should list all, and only, nodes in your cluster.
Get-ClusterGroup
Name OwnerNode State---- --------- -----Available Storage NODE3 OfflineCluster Group NODE1 OnlineAGGPA001 NODE2 Online
NOTE: For an Always On Availability Group you would not necessarily expect shared storage, so a State of Offline is fine (if you were using an Always On FCI it is not).
Get-ClusterResource
Name State OwnerGroup ResourceType---- ----- ---------- ------------Cloud Witness Online Cluster Group Cloud WitnessCluster IP Address Online Cluster Group IP AddressCluster Name Online Cluster Group Network NameAGGPA001 Online AGGPA001 SQL Server Availability GroupAGGPA001_10.90.195.38 Offline AGGPA001 IP AddressAGGPA001_10.92.195.38 Online AGGPA001 IP AddressAGGPA001_SQLAGLSTN01 Online AGGPA001 Network Name
NOTE: If the Listener is configured with multiple IP addresses for different subnets, only the IP for the current subnet comes online. The other remains offline until failover to a node in that subnet.
Resolve-DnsName AGCLUSTER
Name Type TTL Section IPAddress---- ---- --- ------- ---------AGCLUSTER.mydomain A 1200 Answer 10.92.195.36
Get-ClusterResource "AGGPA001_10.90.195.38" | fl *
Characteristics : 0Cluster : AGCLUSTERDeadlockTimeout : 300000Description :Id : 75f12454-b6d5-4602-8031-956f5c6c6225IsCoreResource : FalseEmbeddedFailureAction : 2IsAlivePollInterval : 4294967295IsNetworkClassResource : TrueIsStorageClassResource : FalseLastOperationStatusCode : 8589934592LooksAlivePollInterval : 4294967295MaintenanceMode : FalseMonitorProcessId : 7204Name : AGGPA001_10.90.195.38OwnerGroup : AGGPA001OwnerNode : NODE2PendingTimeout : 180000PersistentState : 1ResourceSpecificData1 : 0ResourceSpecificData2 : 0ResourceSpecificStatus :ResourceType : IP AddressRestartAction : 2RestartDelay : 500RestartPeriod : 600000RestartThreshold : 1RetryPeriodOnFailure : 600000SeparateMonitor : FalseState : OfflineStatusInformation : 0
Get-ClusterParameter -InputObject (Get-ClusterResource "AGCLUSTER_10.92.195.38")
Object Name Value Type------ ---- ----- ----AGGPA001_10.92.195.38 Network Cluster Network 1 StringAGGPA001_10.92.195.38 Address 10.92.195.38 StringAGGPA001_10.92.195.38 SubnetMask 255.255.255.240 StringAGGPA001_10.92.195.38 EnableNetBIOS 0 UInt32AGGPA001_10.92.195.38 OverrideAddressMatch 0 UInt32AGGPA001_10.92.195.38 EnableDhcp 0 UInt32AGGPA001_10.92.195.38 ProbePort 0 UInt32AGGPA001_10.92.195.38 ProbeFailureThreshold 0 UInt32AGGPA001_10.92.195.38 LeaseObtainedTime 01/01/0001 00:00:00 DateTimeAGGPA001_10.92.195.38 LeaseExpiresTime 01/01/0001 00:00:00 DateTimeAGGPA001_10.92.195.38 DhcpServer 255.255.255.255 StringAGGPA001_10.92.195.38 DhcpAddress 0.0.0.0 StringAGGPA001_10.92.195.38 DhcpSubnetMask 255.0.0.0 String
Get-ClusterParameter -InputObject (Get-ClusterResource "AGGPA001_10.90.195.38")
Object Name Value Type------ ---- ----- ----AGGPA001_10.90.195.38 Network Cluster Network 2 StringAGGPA001_10.90.195.38 Address 10.90.195.38 StringAGGPA001_10.90.195.38 SubnetMask 255.255.255.240 StringAGGPA001_10.90.195.38 EnableNetBIOS 0 UInt32AGGPA001_10.90.195.38 OverrideAddressMatch 0 UInt32AGGPA001_10.90.195.38 EnableDhcp 0 UInt32AGGPA001_10.90.195.38 ProbePort 0 UInt32AGGPA001_10.90.195.38 ProbeFailureThreshold 0 UInt32AGGPA001_10.90.195.38 LeaseObtainedTime 01/01/0001 00:00:00 DateTimeAGGPA001_10.90.195.38 LeaseExpiresTime 01/01/0001 00:00:00 DateTimeAGGPA001_10.90.195.38 DhcpServer 255.255.255.255 StringAGGPA001_10.90.195.38 DhcpAddress 0.0.0.0 StringAGGPA001_10.90.195.38 DhcpSubnetMask 255.0.0.0 String
GetClusterAccess
IdentityReference AccessControlType ClusterRights----------------- ----------------- -------------NT AUTHORITY\SYSTEM Allow FullNT AUTHORITY\NETWORK SERVICE Allow ReadBUILTIN\Administrators Allow FullBUILTIN\Storage Replica Administrators Allow FullNODE1\SQLServer2005SQLBrowserUser$NODE1 Allow FullNODE1\SQLServerHADRUser$MSSQLSERVER Allow FullNT SERVICE\KtmRm Allow FullNT SERVICE\MSDTC Allow FullS-1-5-80-4130899010-3337817248-2959896732-3640118089-1866760602 Allow FullNT SERVICE\smphost Allow FullS-1-5-80-1071656157-3689046577-4105049408-574495319-1522408424 Allow FullS-1-5-80-1116079416-1731319938-396994126-3102800949-670876498 Allow Full
Get-ClusterDiagnosticInfo
Writing to path : C:\Users\mike\HealthTest\Script Version : 0.1Date of capture : 10/13/2026 20:16:21
<<< Phase 1 - Cluster Overview >>>
Getting Info for cluster .
Got Groups Resources
Got remainder cluster objects & exporting groups resources
Exporting remaining objects
Getting cluster propertiesWARNING: Cannot use winrm to connect to all up NodesWARNING: Cannot use winrm to connect to node NODE3WARNING: Only gathering a subset of logs, run command on every node to get all data<<< Phase 6 - Recent Error events >>>
Starting Export of Cluster Logs...Exporting Event Logs...Copying Event Logs....Processing Event Logs...Gathering System Info and Minidump files ...Receiving Cluster Logs...
Mode LastWriteTime Length Name---- ------------- ------ -----a---- 13/10/2026 20:17 67885370 NODE1.mydomain_cluster.log-a---- 13/10/2026 20:17 63849728 NODE2.mydomain_cluster.log-a---- 13/10/2026 20:17 51189818 NODE3.mydomain_cluster.logAll Logs Received
Summary of Error Events (in the last 24 hours) by LogName and EventId
LogName EventId N5 N6 Total Message------- ------- -- -- ----- -------Storage-Storport/Operational <549> 27 27 54 This is the first instance of the error seen during this time perio...Application <3041> 29 0 29 BACKUP failed to complete the command BACKUP LOG LIVE_AUTO_DAG. Che...SmbClient/Connectivity <30803> 14 0 14 Failed to establish a network connection....Storage-ClassPnP/Operational <507> 5 5 10 Completing a failed non-ReadWrite SCSI SRB requestSystem <10028> 5 3 8 DCOM was unable to communicate with the computer ukeq-cert002.parag...Application <13> 5 3 8 Certificate enrollment for pgcc-uk\admin_tgopikrishna failed to enr...Application <6> 5 3 8 Automatic certificate enrollment for local system failed (0x800706b...Application <82> 5 3 8 Certificate enrollment for Local system failed in authentication to...Application <8198> 3 1 4 License Activation (slui.exe) failed with the following error code:...SmbClient/Connectivity <30800> 4 0 4 The server name cannot be resolved....Application <1000> 1 0 1 Faulting application name: dcconfig.exe, version: 1.0.0.0, time sta...Clustering-Manager/Admin <4657> 1 0 1 Failover Cluster PowerShell cmdlet Get-Cluster: You do not have adm...
<<< Phase 7 - Compacting files for transport >>>
Creating zip file with objects, logs and events.Cleaning up temporary directory C:\Users\mike\HealthTest\Zip File Name : C:\Users\mike\HealthTest-AGCLUSTER-20261013-2016.ZIP
<<< Phase 1 - Cluster Overview >>>
Getting Info for cluster .
Got Groups Resources
Got remainder cluster objects & exporting groups resources
Exporting remaining objects
Getting cluster propertiesWARNING: Cannot use winrm to connect to all up NodesWARNING: Cannot use winrm to connect to node NODE3WARNING: Only gathering a subset of logs, run command on every node to get all data<<< Phase 6 - Recent Error events >>>
Starting Export of Cluster Logs...Exporting Event Logs...Copying Event Logs....Processing Event Logs...Gathering System Info and Minidump files ...Receiving Cluster Logs...
Mode LastWriteTime Length Name---- ------------- ------ -----a---- 13/10/2026 20:17 67885370 NODE1.mydomain_cluster.log-a---- 13/10/2026 20:17 63849728 NODE2.mydomain_cluster.log-a---- 13/10/2026 20:17 51189818 NODE3.mydomain_cluster.logAll Logs Received
Summary of Error Events (in the last 24 hours) by LogName and EventId
LogName EventId N5 N6 Total Message------- ------- -- -- ----- -------Storage-Storport/Operational <549> 27 27 54 This is the first instance of the error seen during this time perio...Application <3041> 29 0 29 BACKUP failed to complete the command BACKUP LOG LIVE_AUTO_DAG. Che...SmbClient/Connectivity <30803> 14 0 14 Failed to establish a network connection....Storage-ClassPnP/Operational <507> 5 5 10 Completing a failed non-ReadWrite SCSI SRB requestSystem <10028> 5 3 8 DCOM was unable to communicate with the computer ukeq-cert002.parag...Application <13> 5 3 8 Certificate enrollment for pgcc-uk\admin_tgopikrishna failed to enr...Application <6> 5 3 8 Automatic certificate enrollment for local system failed (0x800706b...Application <82> 5 3 8 Certificate enrollment for Local system failed in authentication to...Application <8198> 3 1 4 License Activation (slui.exe) failed with the following error code:...SmbClient/Connectivity <30800> 4 0 4 The server name cannot be resolved....Application <1000> 1 0 1 Faulting application name: dcconfig.exe, version: 1.0.0.0, time sta...Clustering-Manager/Admin <4657> 1 0 1 Failover Cluster PowerShell cmdlet Get-Cluster: You do not have adm...
<<< Phase 7 - Compacting files for transport >>>
Creating zip file with objects, logs and events.Cleaning up temporary directory C:\Users\mike\HealthTest\Zip File Name : C:\Users\mike\HealthTest-AGCLUSTER-20261013-2016.ZIP
Connect to Cluster
Before we can continue (to correct issues or otherwise) we need to connect to the cluster...Connect to Cluster
Cluster Quorum Configuration
Cluster Quorum Configuration
File Share Witness
File Share Witness
In this example we are going to use a File Share from our Domain Controller (DC01).
Think long and hard before you use a production Domain Controller for anything other than being a Domain Controller. In this case there are only three machines in MYDOMAIN (SQL01, SQL02 and DC01). Alternatives are: to use a share from my VirtualBox host, or add another server to the domain.On DC01 I did this...mkdir C:\Quorumnet share quorum /GRANT:MYDOMAIN\Administrator,fullThe witness file share must not be on a node that already participates in the WSFC configuration
The witness file share can be a share from a node that participates in another WSFC configuration
The witness file share must exist in the same Active Directory Domain as the WSFC
The WSFC cluster service account must have read and write permissions to the witness file share
Set-ClusterQuorum -FileShareWitness \\fileserver\witness
(TODO: Make this clearer)
Get-ClusterQuorum
Set-ClusterQuorum -NodeMajority
Set-ClusterQuorum -NodeAndFileShareMajority \\myserver\myshare
To check vote settings...
Get-ClusterNode | fl NodeName, NodeWeight
To change vote settings...
Get-ClusterNode "MYNODE3").NodeWeight=0
The above sets MYNODE3 to not have a vote. Use 1 to set it so it does have a vote.Next Steps
Next Steps
Bibliography
Bibliography
https://docs.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-R2-and-2012/hh831579(v=ws.11)https://www.brentozar.com/archive/2011/07/how-set-up-sql-server-denali-availability-groups/https://docs.microsoft.com/en-us/sql/sql-server/failover-clusters/windows/wsfc-quorum-modes-and-voting-configuration-sql-server?view=sql-server-ver15https://docs.microsoft.com/en-us/sql/sql-server/failover-clusters/windows/windows-server-failover-clustering-wsfc-with-sql-server?view=sql-server-ver15https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2008-R2-and-2008/cc730649(v=ws.10)
https://learn.microsoft.com/en-us/powershell/module/failoverclustershttps://learn.microsoft.com/en-us/powershell/module/failoverclusters/get-clusterhttps://learn.microsoft.com/en-us/powershell/module/failoverclusters/get-clusterdiagnosticinfohttps://learn.microsoft.com/en-us/powershell/module/failoverclusters/get-clusternodehttps://learn.microsoft.com/en-us/powershell/module/failoverclusters/get-clustergrouphttps://learn.microsoft.com/en-us/powershell/module/failoverclusters/get-clusterresourcehttps://learn.microsoft.com/en-us/powershell/module/failoverclusters/get-clusterparameterhttps://learn.microsoft.com/en-us/powershell/module/failoverclusters/new-clusterhttps://learn.microsoft.com/en-us/powershell/module/failoverclusters/test-cluster
https://learn.microsoft.com/en-us/powershell/module/dnsclienthttps://learn.microsoft.com/en-us/powershell/module/dnsclient/resolve-dnsname
https://learn.microsoft.com/en-us/powershell/module/failoverclustershttps://learn.microsoft.com/en-us/powershell/module/failoverclusters/get-clusterhttps://learn.microsoft.com/en-us/powershell/module/failoverclusters/get-clusterdiagnosticinfohttps://learn.microsoft.com/en-us/powershell/module/failoverclusters/get-clusternodehttps://learn.microsoft.com/en-us/powershell/module/failoverclusters/get-clustergrouphttps://learn.microsoft.com/en-us/powershell/module/failoverclusters/get-clusterresourcehttps://learn.microsoft.com/en-us/powershell/module/failoverclusters/get-clusterparameterhttps://learn.microsoft.com/en-us/powershell/module/failoverclusters/new-clusterhttps://learn.microsoft.com/en-us/powershell/module/failoverclusters/test-cluster
https://learn.microsoft.com/en-us/powershell/module/dnsclienthttps://learn.microsoft.com/en-us/powershell/module/dnsclient/resolve-dnsname
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