July 25, 2008 at 10:32 am
The rule is ALWAYS "It depends"
There are print servers that overload hardware and there are SQL instances that could run alongside almost any other software.
Virtualization is about using more of the hardware resources available, more efficiently. Getting closer to 90% or even 100% value from your hardware by combining things. That brings with is less space, less power/cooling, etc.
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July 28, 2008 at 4:36 am
As above it depends.
We cluster our SQL using Polyserve, this allows multiple instances to be installed onto multiple servers, also provides easy SAN management as you can grow LUNS on the fly using "spare" LUN's etc. Thus providing very rapid failover (but there is a 15-30 second down / up)
We do occasionally use VM for SQL but very rarely and only where they require dedicated SQL server due to historical / political issues...
We have hundreds of Prod VM servers running on 25-30 ESX hosts, again as above if you have issues with hardware / networking especially DNS / SAN etc VMWare won't magically solve these.
Especially with ESX 3.5 (and the latest update that came out last Friday), there's some amazing features such as live cloning whereby you can clone to another image file. So long as the API's are there which I'm pretty sure they are, for some people being able to live clone production into AT / DR etc will be extremely handy.
HA + DRS are very powerful tools, in 3.5 latest update, they can now monitor inside a VM and restart it if it crashes for any reason.
We haven't used SAN replication yet however it is something that will be introduced soon.
Steve, I might consider writing something however as we haven't virtualised too much SQL it would predominently based around Windows virtualisation with some SQL flavour?
With ESX server you can provide a RAW mapping (aka RDM) for the virtual machine to be able to see a LUN as normal, however I think they're still limited to 2TB extents.
I've not experienced Hyper V yet, TechEd last year showed some of the features and I expect it to grow quickly but at the moment it just doesn't rival ESX in terms of features / proven stability.
P2V / P2P / V2P are all possibilities, I think we've used some HP tools to allow P2P before and this has proven very handy.
For extremely demanding tasks then physical is probably the way forwards, my VMware instructor stated that VMWare wasn't solely for performance, but consolidation where sensible, file / print etc Howerver I've seen VMWare + SQL PDF's or brochures where they scaled up to very high workloads on SQL + ESX.
Give it a try, you'll probably like it 🙂
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