Virtualization planning advice.
Posted on 2013-01-12
We are getting ready to purchase a setup for virtualizing our servers. I’m looking for suggestions/recommendations on performance.
We have 5 servers in service and are planning to add 3 new ones once we have the Virtual boxes running. In total counting future expansion I’m trying to plan for 10 to 12 servers and 4 Windows 7 machines. All of the servers will run Windows 2008 Standard.
1. DC, WSUS
2. email server (not exchange) lowest IOPs at 8
3. 3 or 4 SQL databases that will run on the rest of the servers which are just standard application and file servers. Some are considered Tier 1 apps. 1 SQL db is somewhat large but the rest are small.
The Dpack results ranged anywhere from 8 to 25 IOPs per server. 5 servers at the 95% were 111 IOPs . Dell tells me the Eqaulogic PS4100E will work with 800ish IOPs.
2x Dell 620 servers: 2x E-2620 2.00 GHZ 6 core 15MB cache, 96GB memory, 2x 146GB 15k drives.
2x 6424 Switches
1 Equallogic PS4100E with 12x 1TB drives. Gives over 6TB of space (We have 1.3TB of space used across the 5 servers)
V5 Essential Plus kit.
My concerns are with the storage array. Can you expect the same IOPs out of these servers in the virtual world? I’m estimating that we should be around 300 IOPs with all the planned servers running.
Would this give us room for the small percentage of times when a server does peak out? 300 of 800 kind of worries me when some of those servers peaked much higher than 800 in DPacks. (During database backups and backups.). I will be planning backups and scans to run at different times.
My other options would be a PS6100e with 24x 1TB 7k drives or PS4100x with 12x 900GB 10k drives. Of course price is the main driver for the decision. The 4100x is most expensive followed by the 6100e and then the 4100e. I know there are other solutions out there but we are pretty much restricted to Dell.
From other posts I have read and what I’m seeing from the Dpacks I feel like it’s safe to say we will see the 20 to 50 IOPs per server. If that’s the case can you make the argument that 800 IOPs / 50 per VM would net 16 VM running and would be max for this array?
I’ve also seen a lot of discussion about not using 7k drives for VMs because they would limit performance. If arrays are all about the IOPs/spindles does it really matter what drives are in it as long as you know the IOPs you’re getting out of it? Our current 2950s are using 10k and some 15k drives.
Any advice or opinions are welcomed. I’m just trying to get outside information (non vender).
Thanks for the help