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BravehearT1326
Starting Member
24 Posts |
 Posted - 2010-10-25 : 11:09:57
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| Hi there - can anyone advise on the potential issues / pitfalls with the following environment.2 node Cluster (Active / Passive) both machines VM's running on seperate physical hosts. Shared SAN storage between 2 servers to allow for Microsoft clustering & SQL2005 to be installed and configured for failover. Data availability does not appear to be the primary factor here with Application availability being the most important thing.....but in my opinion the 2 go hand in hand. Its no use having an applicaton that you can logon if there's no data behind it.I believe that using VMware and Clustering can cause issues with regards to patching, Data high availability, application availability etc but looking to get an overall picture of the pros and cons of both.Yes VMware snapshot technology is a nice to have for the likes of patching etc - however my understanding this that this does not work with shared disk storage and Microsoft clustering. Is this the case?Data availability - well snapshots of the data can be taken at a SAN level but is this the best method to employ.Would a Single VM machine running SQL server and possibly deploying SQL Mirroring be a valid option here and give greater coverage incase of an outage. VM could be snapshot - data would be mirrored elsewhere - downtime and data loss kept at a min?All opinions appreciated on this. |
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russell
Pyro-ma-ni-yak
5072 Posts |
Posted - 2010-10-25 : 13:26:47
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| You can build your cluster on VMs as long as they are on different physical hosts (as you said).VMWare snapshots are nice to have for the VM, but are no substitute for native SQL Server backups.You'll want to be very careful with what other virtual servers share the same resources (are on the same physical host) as your SQL Server(s). You can, and should, overallocate resources, but you'll have massive performance problems and system hangs if the physical resources are actually all in use.I don't see aany issues with patching or HA at all.What you need to know is how many resources need to be allocated to the VM and make sure that they are always available if this is a mission critical app.Finally, when you say "application availability" if you mean placing the application on the cluster...well, is the app cluster aware? What will cause the app to failover if it is not? |
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russell
Pyro-ma-ni-yak
5072 Posts |
Posted - 2010-10-25 : 13:29:39
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| Regarding SAN level snapshots...what type of SAN(s) are you using?They are useful, but are no replacement for native backups unless:1. You have a DR site with the same SAN2. You're mirroring your snapshots to the DR site3. Every server you may want to restore to is also on the SAN (or same kind of SAN) |
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SQL Clusterning and VMware High Availability