Storage Device - DS3300 - Multiple Logical Drives?

I have two new IBM x3650 M3 servers and a DS3300 storage device. I have created a single array with RAID 10. I will be using Hyper-v to create and manage VM's that will access the DS3300. Should I create multiple logical drives or just one and configure my VHD's accordingly?

Host-1 will have an SQL VM and possibly one or two very low impact VM's
Host-2 will have Exchange, File & Print, Office Comm, Storage.

O/S's will be 2008
comteksoAsked:
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DavidPresidentCommented:
Well, as you mentioned, I/O overhead is nominal, so in the grand scheme of things, it doesn't matter.  Yes, you get another I/O queue for some caching, but no matter how you set it up, every read and write regardless of the VM is going to hit the same RAID10 disks.
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PowerToTheUsersCommented:
Will those two hosts be clustered? Are you going to make a Hyper-V LiveMigration-setup? If that's the case, you have the choice to make it one big or two smaller LUNs.

If those VMs will always stay on the same host, and the hosts will not be clustered, you will at least need to make two LUNs, one connected (presented) to each host.

So that leaves the choice to put VMs together on one LUN, ore make a LUN per VM. As dlethe stated, performance-wise both solutions are good. But I usually put my VMs together on a single LUN, especially using Dynamical VHDs. That gives flexibility to "consolidate" the free space. I prefer to have one LUN with much free space, instead of having multiple LUNs, each with a little bit of free space. On the other hand you have to make sure you have enough storage (or extend the LUN) to allow all VM's to eventually expand their VHDs to their maximum size.

An example will it more clear: suppose you have 5 VM's, you give each a VHD of 20GB (dynamic), but after installation the VHDs only have grown to 5GB.
If you have one LUN with all VHDs, you would have only 25GB of it used, but you have to take into account those VHD's can be expanded to 5x20 = 100GB eventually. So either you have only a LUN of 30GB and expand it later, or you can use the free 75GB for temporary (test?) machines in the mean time.
If you make one LUN per VM, you would need to make 5 LUNs, each at least 5GB, but preferably 20GB. That way you will a have a bit of free space on each LUN, and more LUNs to manage on your storage device.
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