June 11, 2015 at 4:26 am
Hi,
We are in the process of building a 3 node SQL Server Cluster (Server 2012/ SQL Server 2012), and we have configured the quorum so that all 3 nodes have a vote (no file share witness as we already have an odd number of nodes).
As I understand it, this should allow the cluster to run as long as 2 of the nodes remain online.
However, the validation report states that 2 node failures would be acceptable and, when we tested this by powering off two of the nodes, the cluster did indeed continue to run on a single node.
Can anyone advise why this might be the case?
Thanks,
J
June 11, 2015 at 4:45 am
DBANewbie (6/11/2015)
we have configured the quorum so that all 3 nodes have a vote (no file share witness as we already have an odd number of nodes).
Sounds reasonable
DBANewbie (6/11/2015)
As I understand it, this should allow the cluster to run as long as 2 of the nodes remain online.However, the validation report states that 2 node failures would be acceptable and, when we tested this by powering off two of the nodes, the cluster did indeed continue to run on a single node.
Can anyone advise why this might be the case?
Thanks,
J
Yes, traditionally 2 out of 3 votes would keep the cluster up. Which Operating system are you using though?
Windows 2012 uses a new feature called dynamic vote configuration. During the planned shutdown of nodes the voting is recalculated to keep the cluster online.
Please post the results of this Powershell query
get-clusternode | ft id,nodename,dynamicweight,nodeweight
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"Ya can't make an omelette without breaking just a few eggs" 😉
June 11, 2015 at 4:57 am
Thanks very much for the reply, I will check this and advise on the outcome.
June 11, 2015 at 6:21 am
It was indeed the use of dynamic quorum which was allowing us to run on the single node following graceful shutdowns on the other nodes.
Thanks very much for your help with this.
June 11, 2015 at 7:47 am
Yep, if you pull the plug suddenly on both nodes the cluster should go offline as it wont have chance to recalculate the dynamic votes
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"Ya can't make an omelette without breaking just a few eggs" 😉
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