October 27, 2014 at 1:36 pm
I have seen many recommendations stating that if you have an even number of nodes, then you should create a fileshare witness (for the 3rd quorum vote). I would like to better understand this...
I have a test AlwaysOn cluster, with 2 nodes an no fileshare witness. During my testing, if I, for example:
1. Reboot the active node, then the cluster fails over to the secondary node as expected.
2. Reboot the secondary node, the primary is not affected.
So, everything works as I want it to, and I don't have the undesirable situation where rebooting the secondary node affects the primary.
Having said this, what would a fileshare witness (3rd quorom vote) buy me?
TIA.
October 27, 2014 at 2:09 pm
bbcolo22 (10/27/2014)
I have seen many recommendations stating that if you have an even number of nodes, then you should create a fileshare witness (for the 3rd quorum vote). I would like to better understand this....
Firstly, the witness (disk or fileshare) is not AlwaysOn specific, it's required by the Windows Server Failover Cluster to maintain quorum during node failures.
bbcolo22 (10/27/2014)
I have a test AlwaysOn cluster, with 2 nodes an no fileshare witness. During my testing, if I, for example:1. Reboot the active node, then the cluster fails over to the secondary node as expected.
2. Reboot the secondary node, the primary is not affected.
So, everything works as I want it to, and I don't have the undesirable situation where rebooting the secondary node affects the primary.
Having said this, what would a fileshare witness (3rd quorom vote) buy me?
TIA
Are your cluster nodes using Windows 2012?
Are the cluster nodes on the same physical site?
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"Ya can't make an omelette without breaking just a few eggs" 😉
October 27, 2014 at 3:00 pm
Perry Whittle (10/27/2014)
bbcolo22 (10/27/2014)
I have seen many recommendations stating that if you have an even number of nodes, then you should create a fileshare witness (for the 3rd quorum vote). I would like to better understand this....Firstly, the witness (disk or fileshare) is not AlwaysOn specific, it's required by the Windows Server Failover Cluster to maintain quorum during node failures.
Right, I understand that.
bbcolo22 (10/27/2014)
I have a test AlwaysOn cluster, with 2 nodes an no fileshare witness. During my testing, if I, for example:1. Reboot the active node, then the cluster fails over to the secondary node as expected.
2. Reboot the secondary node, the primary is not affected.
So, everything works as I want it to, and I don't have the undesirable situation where rebooting the secondary node affects the primary.
Having said this, what would a fileshare witness (3rd quorom vote) buy me?
TIA
Are your cluster nodes using Windows 2012?
Are the cluster nodes on the same physical site?
I am using Windows 2012R2. I actually have 2 test clusters - one is with 2 machines in the same room and the other cluster is on machines in different parts of the country (Denver and KY). They both show the same behavior.
October 27, 2014 at 3:15 pm
bbcolo22 (10/27/2014)
I am using Windows 2012R2.
Ok, Windows 2012 and 2012 R2 have a new feature called Dynamic Node Weight configuration. During a planned outage such as a shutdown the quorum votes reconfigure to maintain cluster quorum.
Run the following powershell query with both nodes online and with one cleanly shutdown and compare the results.
Get-ClusterNode | ft id,nodename,dynamicweight,nodeweight
bbcolo22 (10/27/2014)
I actually have 2 test clusters - one is with 2 machines in the same room and the other cluster is on machines in different parts of the country (Denver and KY). They both show the same behavior.
Try an unplanned node failure
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"Ya can't make an omelette without breaking just a few eggs" 😉
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