StoreVirtual Storage
Showing results for 
Search instead for 
Did you mean: 

VSA & ESX scsi reservations

Occasional Contributor

VSA & ESX scsi reservations

Hi All,

I am using HP servers running ESX4, and has qlogic/Emulex HBAs.

We have a large FC storage (SAN) that doesn't support scsi persistent reservations that is required by ESX.

We want to use this storage on our ESX servers (no clusters), and we are looking at ways to over come the scsi reservation requirement of native ESX.

If I install VSA on the ESX, does it take control over the SCSI layer of ESX ?

Does VSA require scsi persistent reservation toward the block devices (SAN)
(Which leave me with the same problem)

Or it doesn't ?

and that solves my problem, and I can use that storage, and even gives me additional value of storage virtualization.

In this manner the VSA will provide the scsi reservation toward the ESX, but will enable me to use my storage, that doesn't support scsi presistent reservation.

Any advise would be useful
Thanks !!
Respected Contributor

Re: VSA & ESX scsi reservations

Since the VSA runs as a VM on your ESX host, you will need to somehow present that storage as a VMFS datastore (or raw device mapping) within ESX/vSphere.

That being said, since the storage in this case is ONLY presented on 1 ESX host (and not shared storage) I'm not sure if it would present any problems for you.

Are you UNABLE to mount the device, or is it just "unsupported" for persistent reservations?

I did something similar for a customer (actually we removed the FC out of the loop, and just attached the drive trays from the legacy SAN as DAS via external U320 SCSI RAID)

VSA does not take over the SCSI or iSCSI of ESX. It is actually just a virtual machine, and it is using a virtual switch and network (it just happens to be your iSCSI network) to communicate with hosts.

So on your vSwitch for your VSA you will need a VM Network portgroup for the VSA to talk to the rest of the iSCSI LAN, you will also need a VMkernel portgroup, for the local ESX host to talk to this VSA (and any other VSA/LeftHand or iSCSI targets on your iSCSI LAN)

Be sure to use enough physical NICs (best to try to separate iSCSI kernel, vmotion, vm network, and provide redundancy on all these if possible).

As long as you can present the SAN storage to your ESX host somehow, you then your concept should work just fine, but the VSA itself won't overcome any technical limitations of ESX attaching to a particular physical storage array.
Uwe Zessin
Honored Contributor

Re: VSA & ESX scsi reservations

> support scsi persistent reservations that is required by ESX.

I thought that vSphere still uses 'simple' SCSI-2 reservations...

If the storage cannot provide the ESX requirements, it is very likely that this is an 'unsupported ESX configuration' anyway. And even if non-shared access works (more by accident than by design) the VSA is not supported in such an environment.

Now, if this isn't for daddy's mission critial environment - try it out.