September 8, 2014 at 7:18 am
We are getting mixed information from various sources while researching the possibility of creating three node SQL Server clusters on VMware virtual machines.
Is it *possible* to build a *three* node SQL Server 2012 SP2 cluster, running on Windows Server 2008 R2, on VMware virtual machines? Some material says that three node clusters are not supported by VMware, but we don't know whether that means:
1) The VMware support folks simply have not tested a three node SQL Server cluster on VMware
2) Is not possible to build a three node SQL Server cluster on VMware
3) It is possible, but not wise (for some technical reason) to build a three node SQL Server cluster on VMware
4) Or something else...
Can anyone share their experiences on this topic?
Thanks,
J
September 8, 2014 at 7:43 am
I don't know why it would not be possible. The VM's will be acting just like standalone servers, so there shouldn't be any reason why you cannot have an active/passive/passive cluster.
Are all the servers in the same location? Are you running each SQL node on separate VM hosts?
I assume, you are trying to protect against issues with the hardware itself, but if that is a worry then having at least two VM hosts in a cluster would protect you somewhat and you would only need 2 nodes as having 3 could potentially mean you lose two nodes if the hardware went down. They should then all come up on the second VM host though.
Clustering SQL Server in a virtualised environment is more beneficial for maintenance purposes (patching etc), rather than high availability.
EDIT:
This article seems to explain it.
It seems there is issues with having more than 2 nodes due to the increase likely hood of failover when performing hardware configuration changes.
September 8, 2014 at 8:28 am
shew (9/8/2014)
We are getting mixed information from various sources while researching the possibility of creating three node SQL Server clusters on VMware virtual machines.Is it *possible* to build a *three* node SQL Server 2012 SP2 cluster, running on Windows Server 2008 R2, on VMware virtual machines? Some material says that three node clusters are not supported by VMware, but we don't know whether that means:
1) The VMware support folks simply have not tested a three node SQL Server cluster on VMware
2) Is not possible to build a three node SQL Server cluster on VMware
3) It is possible, but not wise (for some technical reason) to build a three node SQL Server cluster on VMware
4) Or something else...
Can anyone share their experiences on this topic?
Thanks,
J
If you're planning to use Failover Cluster Instances in your AlwaysOn configuration then this is where the restriction lies (shared storage).
Multi node clusters for AlwaysOn with no FCI are supported (no shared storage).
It's in the link posted by the previous user
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"Ya can't make an omelette without breaking just a few eggs" 😉
September 8, 2014 at 8:30 am
>>Are all the servers in the same location?
Yes.
>>Are you running each SQL node on separate VM hosts?
We would prefer to do so.
Actually, that link is why I posted the question. One of our internal folks forwarded it to me earlier today. I'm a DBA, not a VMware expert, so I am not fully aware of what that link is saying. To me it sounds as if, yes, it is possible, but it is not *desirable* from a VMware standpoint.
I ran across a vendor with what appeared to be strong VMware knowledge at a recent SQL Server conference, and he seemed to think creating a three node cluster on VMware was possible.
I know that our internal VMware team is very fond of vMotion. What are the ramifications of the RDM storage limitation of 2 in the link?
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