HP VSA, ESXi 4.1, and 2 TB Hard Drives

Last Updated: 7/23/10

We were going to setup:
- HP's Virtual San Appliance (VSA)
- Using VMware ESXi 4.1
- 2 TB hard drives attached via MD1000 to a PowerEdge R710

Turned out that this arrangement is not compatible without losing 50% of our disk space. The cause of the problem is Vmware's VMFS can only go up to 2 TB (without using extends). Extends only work with different logical volumes, so extends won't solve the problem of formatting a 10 TB RAID-5 volume.

So, VMware likes to see storage space provided as 2 TB chunks or smaller, with 2 TB drives this is hard to accomplish unless you create lots of two drive RAID-1's, thus wasting 50% of your disk space. The other option is Raw Device Mapping (RDM) which allows a VM to access a physical disk or LUN directly without having to format with VMFS first. However, Dell PERC's (Raid controllers) do not support RDM.

So if you are thinking of using this setup, don't. Here are some possible solutions:

- Use non PERC raid controllers that support RDM
- Purchase the HP P4300 SAN
- Wait for VMware to break the 2 TB VMFS barrier.
- Use smaller hard drives

Keywords: hp virtual san appliance vsa esxi esx 4.0 4.1 dell md1000 2TB hard drive lun vmfs