I have a 3 node cluster.

All of the nodes are part of Cluster01 in what should be A/A/P mode.

Usually instanceA and instanceB of SQL Server would reside on NodeA and NodeB respectively. the windows cluster resources would reside on NodeA and NodeC would be the passive node.

Currently, our configuration is as follows:

  • NodeA has the cluster resource group which contains the Quorum, Windows Cluster IP and HostName as well as the MSDTC
  • NodeB has instanceA of SQL Server with it's own IP and HostName
  • NodeC has instanceB of SQL Server with it's own IP and HostName

My question is, while i know that usually a failover would cause some downtime, given that our SQL Server instances have their own IP and HostName and users are connected to those, would failing over the Quorum, Windows IP/Host and the MSDTC interrupt the SQL service in any way?

I've checked that there are no dependencies to the Windows Cluster, but is that a bit like saying if i pull the plug out will Windows still run?

Thanks in advance!

  • I voted to move this to serverfault. Oct 14 '11 at 11:49

No, failing over the other cluster groups (quorum, etc.) will not cause your SQL instances to be affected. SQL listens on its own IP and virtual name.

  • Would the MSDTC failing over with this group interrupt any SQL functions?
    – LeedsDBA
    Oct 17 '11 at 12:14
  • Tried this on our DR site and you're right it didn't seem to interupt our SQL Server instances. My only conern is MSDTC.
    – LeedsDBA
    Oct 18 '11 at 10:15
  • MSDTC can also fail over without affecting SQL Server instances as it has its own IP, etc. Even if you are using distributed transactions, a distributed tran in progress would roll back upon failover. Most SQL installations to my knowledge do not use MSDTC, and it is just there as a default or to support SSIS. Oct 18 '11 at 14:00

Distributed Transactions will be affected by failing over MSDTC.

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