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How To Determine If VAAI is Functioning Through the vSphere Client

Lately I have been getting a lot of questions on how to determine if vSphere APIs for Array Integration is actually functioning on all datastores. There are tons of articles on how to check if it is enabled, but I could not find one on checking if it is functioning.

VAAI is always enabled by default. So, unless you have explicitly disabled it, there is little value in checking whether or not it is enabled. However, checking if it is functioning is something I find useful. With that, I decided to share this with everyone in case you had not seen it.

In the vSphere client, select an ESXi host and click on Configuration | Storage Adapters and select your HBA adapter. As you can see in Fig. 1, examine the last column under the heading Hardware Acceleration. If you see "Supported," that means VAAI is functioning for that particular datastore. This is just a quick and easy way of determining if VAAI is working properly.

Tap, tap, tap. Is this thing on?

Figure 1. Configuring the HBA Adapter. (Click image to view larger version.)

Now, Fig. 1 also shows some entries that say "Unknown." This means one of two things: Either that LUN has not been provisioned into a datastore yet, or that there is a Raw Device Mapping (RDM) attached to one or more VMs.

I hope this helps! And let me know if you're having other problems I can help you with in this blog by writing to me here.

Posted by Elias Khnaser on 10/27/2011 at 5:22 PM


Reader Comments:

Wed, Jan 11, 2012

I found this article VERY helpful. I had been trying to find a way to verify that VAII, MPIO, and several other features were operational upon final configuration of a new server. I was able to find MPIO through my SAN manufacturing documentation but never VAII. During testing I could tell that VAII was working due to the speed of copying within the SAN (about 1/3 to 1/2 the time in some cases). So YES VAII DOES WORK!!!! Maybe your reader has a problem with the SAN manufacturer's implementation of VAII. I've had no problems with 4.0, 4.1, and my dev environment for 5.0 :-)

Fri, Nov 4, 2011 Elias Khnaser Chicago, IL

if the site is bothering you so much, why are you reading it? there are plenty of other sites if you don't like what we are posting. Furthermore, Jason's post addresses UNMAP, one of the features of VAAI which automatically reclaims space when using Thin Provisioning. VAAI is not broken and was never broken. I write on Citrix a ton and on Microsoft a ton. please try and be a bit fair in your comments. thanks. Eli

Tue, Nov 1, 2011

I really wish this site offered balanced virtualization reporting. We've had nothing but problems with VAAI. It was broken in 4.0, 4.1 and now in 5.0. VMware recently released told people to disable VAAI in 5.0. http://www.boche.net/blog/index.php/2011/09/30/vmware-issues-recall-on-new-vsphere-5-0-unmap-feature/ This site appears to be nothing, but a VMware marketing site run by VMware consultants.

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