I am getting this question on a very regular basis:
"We have just upgraded to ESXi 5.0 but we cannot find the VAAI driver on the IBM Website"
The answer? There is no vendor supplied driver because no driver is needed. ESXi 5.0 uses a SCSI T10 compliant set of commands that all vendors need to support for VAAI to work.
But of course in the tradition of all answered questions, it leads to another question:
"Once I have upgraded to ESXi 5.0 how can I tell if VAAI is really working?"
The good news is that it is very easy to spot if ESXi 5.0 has detected a VAAI capable LUN. The moment a new LUN is detected by ESXi 5.0 it tries out an Atomic Test and Set command. If that works, you will see that Hardware Acceleration shows as Supported in vCenter. In the screen capture below I have three datastores, two from XIV and one from Storwize V7000, all presented to an ESXi 5.0 server. I dragged the Hardware Acceleration column over from the right hand side to help with the screen capture (in case your vCenter looks different), but you can see the Hardware Acceleration column shows each DataStore as Supported (and did so the moment the volume was detected).
Of course having seen the Hardware Acceleration Supported message only proves that Atomic Test and Set works. To confirm if XCopy (Hardware Accelerated Move) is working, on SVC or Storwize V7000 we can use the Performance monitoring panel. In the example below I first performed a storage vMotion, moving a virtual machine between two Datastores located on the same Storwize V7000 (running 220.127.116.11 firmware). I then performed a clone of the same virtual machine, where the source was on one datastore and the target was placed on another (but both located on the same Storwize V7000). What you can clearly see is that both operations (storage vMotion and cloning) generated no volume traffic, only MDisk traffic. This means that the ESXi server is doing none of the work and the storage is doing all of the work.
For more examples of how to test VAAI, check out section 9.5.5 Testing VAAI, in the new XIV IBM Redbook draft, XIV Storage System: Host Attachment and Interoperabilty which you can find here:
It documents the following tests:
- Test one: Hardware accelerated Initialization or block zeroing
- Test two: Hardware accelerated move or full copy
The tests can be performed regardless of whether you have an XIV (on code levels 10.2.4a and above) or a Storwize V7000/SVC (on code levels 18.104.22.168 and above).
If upgrading to ESXi 5.0 with IBM Storage, please also be aware of the following knowledge base articles regarding VAAI support with IBM Storage: