ESX 3.5 = Virtual Disk or Raw Device Mapping?

[Paid_Peanuts]

Does anyone know what would be the best implementation of a new file server based upon ESX 3.5 using Server 2008 Datacenter R2?

 

I have created the virtual server which is all well and good - I know 2008 R2 isnt a supported OS yet however this is just for testing purposes at the moment and works perfectly well without VMWare tools installed.

 

The question is when i created the VM i gave it a 40GB C: partition. When i come to add an additional virtual disk - i get presented with "Create a new virtual disk" or "Raw Device Mappings".

 

Has anyone tried out both and found any differences in speed between the two? My existing file servers are based upon "new virtual disk" which resides inside the VM - these have worked well for me in the past however i want to make sure if i am re-designing the system i get the best out of it.

 

The VM's run on IBM x2650 hosts with FC to IBM DS3400 (48 x 300GB 15k SAS)

 

Thanks.

[apaton]

Raw is ideal for that extra bit of performance, I only use for Exchange & SQL type applications. You can loose some flexibility such as VM snapshots.

 

But I always aim to create a virtual disk. (file on vmfs)

 

If you have a Fibre Channel SAN you can utilise technologies like NPIV which is fast and enable's LUN masking per Virtual Machine, ideal for RAW devices.