Clustering Design

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Clustering Design

TST1

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March 15, 2011 at 2:37 am

#236749

Hi,
I would like some advice on whether this design for clustering is appropriate. The plan is to have 1 physical server and 1 vm in a cluster which will then failover with same setup. I don't see why we should include the vm in a cluster as I thought the physical machine will suffice. Any advice well appreciated.
Thanks

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Gail Shaw SSC Guru Points: 1004504 More actions · Answer 1

In clustering the two nodes should be identical. That's hardware, OS, drivers, etc. Clustering a physical box with a virtual is definitely not having two identical nodes.

Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

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Henrico Bekker One Orange Chip Points: 27652 More actions · Answer 2

GilaMonster (3/15/2011)
In clustering the two nodes should be identical. That's hardware, OS, drivers, etc. Clustering a physical box with a virtual is definitely not having two identical nodes.

Correct, although a Physical (primary) and Virtual (Secondary) is not impossible and can be done.

There are some tricks to perform for the virtual though.

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TST1 SSCommitted Points: 1798 More actions · Answer 3

Hi,

Thanks for the info, Henrico do you have any articles of how I could implement the physical/vm side? I know I will need to present the VM as raw devices.

MysteryJimbo SSC-Insane Points: 24203 More actions · Answer 4

GilaMonster (3/15/2011)
In clustering the two nodes should be identical. That's hardware, OS, drivers, etc. Clustering a physical box with a virtual is definitely not having two identical nodes.

The key here is "should" and is therefore recommended for a number of reasons such as the ability to failover and still maintain a consistant level service. Therefore there is nothing stopping you implementing a cluster with different hardware so long as you are willing to support two different servers and their potentially unique issues.

My previous company accepted that in the event of a serious hardware failure, they would accept a reduced capacity server until such a problem could be fixed. We had 3 servers of the same model admittedly. Two were identical and ran their own instance of SQL, the third was a lower spec CPU and reduced RAM.

A side point, Microsoft no longer dictate that a cluster hardware should be on "the list" to be supported as part of Windows 2008.

Perry Whittle SSC Guru Points: 234013 More actions · Answer 5

TST1 (3/15/2011)
Hi,
Thanks for the info, Henrico do you have any articles of how I could implement the physical/vm side? I know I will need to present the VM as raw devices.

Are these ESX server VMs?

What shared storage medium are you using?

clustering a physical box with a VM is perfectly valid, at minimum, ensure they utilise the same operating system and patch level.

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