Matt That IT Guy

Racking And Stacking In A Cloud-Based World


VAAI coming to vSphere Standard

vaaiSome interesting news has come out of VMware recently: VAAI (vStorage API for Array Integration) which was recently limited to the Enterprise and Enterprise Plus editions of vSphere, is now available in vSphere Standard Edition.

If you aren’t familiar with VAAI, in a nutshell it is an API that offloads a lot of IO heaving tasks to the storage device (assuming the device supports it). A good example would be cloning a VM. Without VAAI, vSphere would contact the ESXi server, examine the VM, read a few blocks from the storage device, then write a few blocks to the storage device, and repeat until done. This had a lot of overhead.

With VAAI, vSphere will let the storage device know about what you are doing and allow the device to clone the relevant data, thus removing all the overhead. This can translate into significant time savings along with other advantages.

Now for the kicker …. technically there is nothing stopping you from using VAAI in unlicensed versions of vSphere, except for the EULA. It generally ships turned on by default (although you may need to add some vendor extensions), and if you aren’t licensed it is supposed to be up to you to turn it off (probably not too likely).  You can find a VMware KB article here detailing how to check / enable VAAI.

This change was likely pushed through as VAAI really goes hand in hand with VVOLs which were introduced in vSphere 6. Regardless of the reason why, it is always great to get more value for your buck.

You can read more about the decision over at Cormac Hogan’s blog.

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