VMware and SANs and HBAs oh my!

[CoryS]

Hello there!

I had a question in my head I need help clarifying and was hoping a local would be able to lend a hand!

(Warning: Not from a VM background at all)

If you had a physical box with a fiber channel HBA installed which was attached to a SAN how would your virtual machines go about recognizing the HBA if at all. I am half assuming ESX(i) would pick up the LUN you carved out for that WWID and consider that its datastore and you would configure your VMs off of that.

Actual question: Would the VMs at any point be able to use the single HBA (by order of some VMware magic) in order to carve out additional LUNs for each machine?

I dont see how this would ever be possible but color me temporarily ignorant.

Thanks for looking!

[astorrs]

The physical hardware of the host (including the HBA) is completely abstracted from the VM. The virtual machines don't see the underlying storage, all they would see is virtual disks (essentially files) that are what's actually created on the SAN.

It is possible to offer up a LUN directly to the VM through the use of an RDM but those are much less common and frankly not worth looking at (unless you are dealing with large amounts of pre-existing data you don't want to migrate, MSCS, or want to use application aware array snapshots).

[Daniel333]

The VM is going to see just the drives you create on the LUN for it.

[HeroPsycho]

Originally Posted by Daniel333

The VM is going to see just the drives you create on the LUN for it.

That's not completely accurate. The VM still "sees" a disk controller, not just the LUNs. The disk controller however will still be a virtualized one depending on the virtual hardware presented by the virtualization software, not the FC HBA.

[CoryS]

Great. Thanks! That pretty much settles it