vStorage API for Array Integration (VAAI) and vSphere 4.1
A key new capability of vSphere 4.1 is the new vStorage APIs for Array Integration or VAAI.
The vStorage API has been around, but it’s the “Array Integration” part here that’s new. Storage vendors like EMC and Dell’s EqualLogic have already released VAAI support into some of their storage arrays. So what exactly does VAAI mean for the datacenter?
Chad Sakac has an excellent and detailed post on VAAI which I highly recommend but I want to briefly call attention to a few things here.
As Chad explains in his post this is very similar to Intel VT technology and vSphere 4. If you provide vSphere 4 with the newer Intel CPU’s, vSphere will take advantage of the new capabilities. And much like this, if you add a VAAI-enabled SAN to vSphere 4.1, it will also natively take advantage of the API integration.
In an earlier post I described a scenario where a VM was degraded because snapshots were taking too long to close. What if the snapshot was performed by the SAN rather than being performed within the ESX software? That’s what VAAI can provide.
As Chad notes, EMC found that by using VAAI, the following improvements were noted
- VMware storage operation time reduced by 25% or more (up to 10x).
- ESX Host CPU reduced by 50% or more during these storage operations
- Network Traffic reduced by 99%
Below is a video put together by EMC that demonstrates VAAI in action. There’s more at Chad’s site on VAAI including Powerpoint slides and webcasts.
UPDATE: Here is VMWare’s FAQ on VAAI:
http://kb.vmware.com/kb/1021976 vStorage APIs for Array Integration FAQ