Always On Changing Cluster Configuration

There are situations where you would want to change the Windows cluster configuration so a failover does NOT occur. Failovers can occur due to quorum (error: The Cluster service is shutting down because quorum was lost) can’t be reached for a short period of time when nothing is wrong or there is a network hiccup. Changing the cluster configuration thresholds will help stop failovers that occur outside of your control.

These changes affect the voting nodes and witnesses in the Windows Server Failover Clustering (WSFC). If you have servers on different subnets, you can change a DR server to not be a voting node as long as you have another secondary who is (https://msdn.microsoft.com/en-us/library/hh270280.aspx) or change the WSFC thresholds first to see if this helps with dealing with servers in different subnets.

How to Change the Cluster Configuration Threshold and Delay Settings

Make changes to nodes on the same Subnet

• Connect to one node in the clustered environment
  1. Does not need to be done to every server in the cluster
  2. Should be done if Quorum is on the same subnet
• Open Powershell “Run as Administrator”
• Run the following to check to see what subnet delay and threshold is:
  1. get-cluster |fl *same*
  2. 
• Run the following to change the delay and threshold and verify changes:
  1. (get-cluster).samesubnetdelay = 2000
  2. (get-cluster).samesubnetthreshold = 10
  3. get-cluster |fl *same*
  4. 
• Close Powershell

Nodes on Different Subnets

• Connect to one node in the clustered environment
  1. Does not need to be done to every server in the cluster
  2. Should be done if a secondary node is on a separate subnet
• Open Powershell “Run as Administrator”
• Run the following to check to see what subnet delay and threshold is:
  1. get-cluster |fl *cross*
  2. 
• Run the following to change the delay and threshold and verify changes (crosssubnetdelay can be set to 2000 to 4000 depending on how far the other servers are located):
  1. (get-cluster).crosssubnetdelay = 2000
  2. (get-cluster).crosssubnetthreshold = 10
  3. get-cluster |fl *subnet*
  4. 
• Close Powershell

PowerShell Errors\Fixes

• If you get the following error “The term –get-cluster’ is not recognized…”, run the following so you can run the commands in Powershell.
  1. Verify you are not running “Windows PowerShell (x86)” (Close it if you are)
  2. Re-open PowerShell with “Run as Administrator”
  3. Type: Import-Module FailoverClusters;
  4. 
• 1. If you get the following error “AuthenticationError”, close PowerShell and re-open it with “Run as Administrator”
  2. 

If you would like more help with your Windows cluster configuration get in touch with us today!