How to choose virtual disk for a VM, iSCSI initiator in ESX, iSCSI initiator in OS or RDM

[sgul]

Hi,

We're planning our first VMware environment, using Dell Equallogic PS4000 setup. With Win2k8 VM's.

What I can't seem to find info on is what is the best practise, pros/cons, in presenting virtual disk to a VM.

We will be migrating about 2TB worth of data from old file servers to the VMware environment. How should I be presenting this data to the VM. Should the virtual disk be:

1. Present via iSCSI initiator in ESX to the VM. Should this be on a VMFS or RDM (NTFS formatted) volume on the EQLogic array

2. Present via iSCSI initiator in the OS of the VM. In this case it wouldn't be VMFS but NTFS volume off the EQLogic array.

Is one better than the other, do you loose any advanced features like VM snapshots, vmotion, storage vmotion or EQlogic array snaphots feature etc.

Really appreciate any advice and info you have a similar setup.

Thanks in advance.

[AndreTheGiant]

Performance difference between RDM and VMDK disk are minimal.

So I suggest to use some EQL Volumes for you VMFS datastore.

And for VM where you want to use Windows AutoSnapshot manager you can consider to point directly a EQL Volume (in this case formatted with NTFS) with a guest software initiator.

Andre

[sgul]

Thanks for your resopnse Andre (reminds me of the old WWF wrestler)

So the solution is to use a mix, depending on the requirements of the environment. is that correct ?

1. For volumes where I want to use the EQL autosnapshot manager, I can use iSCSI initiator from the VM OS.

2. For the VM's OS etc. I can use virtual disk presented via ESX iSCSI initiator, on VMFS volume.

I think I've got the concept now. Let me know if I've missed it ?

Thanks again.

[AndreTheGiant]

So the solution is to use a mix, depending on the requirements of the environment. is that correct ?

I suggest to keep it simple...

You need some SAN feature (GPT disk larger than 2 TB, autosnapshot manager, ...)? Add a disk with a guest initiator.

Otherwise use vmdk file.

PS: there is also a version of AutoSnapshot Manager for VMware...

Andre