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vSphere 5 Top 10 Countdown: Swap to SSD and VAAI at #5

The countdown to the number 1 VMware vSphere 5 feature continues, and this time we look at Swap to SSD and VAAI, which are tied in the number 5 slot.

The Swap to SSD feature is of particular interest to me because of its overcommitment potential, especially as it relates to desktop virtualization. This cool new feature allows the VMkernel to automatically detect and tag any SSD storage that the ESXi host has access to, whether it is local storage or network storage. Once detected and tagged, the VMkernel will then instruct the scheduler to take advantage of this storage by allowing the ESXi swap to extend to it.

While I am not suggesting by any means that you use SSD as a replacement for memory (and it still is best practice to add physical RAM if you are swapping), this cool new feature does let you take advantage of SSDs in the amplification of memory overcommitment.

As for vSphere Storage APIs for Array Integration, or VAAI, it has always been one of my favorite storage features. With vSphere 5, it got better. One new capability I am particularly excited about is the automated free disk reclamation for thin provisioned disks.

Prior to vSphere 5, the process of reclaiming free disk space as a result of using thin provisioning was a relatively manual process. I am sure some of us have automated and scripted it, but I still consider this a manual process--you still have to maintain the script. Another capability of VAAI I am excited about is that it now extends support for NFS; it was previously just supported on Fibre Channel.

And yet another cool capability of VAAI is known as NFS Space Reservation, which gives you the capability of reserving space on NFS. With NFS, one of the selling points is that it is thin-on-thin by design--the datastore grows and shrinks automatically. There are times I wished I could reserve all the underlying space and not necessarily have to do thin-on-thin. Now you can accomplish that with the new VAAI.

The last feature of the new VAAI I want to share with you is also around NFS and known as Full Copy, which can offload certain copy operations like "clone" or "deploy from template" from the host to the array. Now before you flame me in the comments, I understand that certain NAS vendors had vCenter plugins that would allow you to do this from within vCenter. The enhancement with vSphere 5 is now you can do it natively using the traditional vCenter commands, provided that your storage vendor can support it, of course.

So, guess what I've got at #4. That's for next time.

Posted by Elias Khnaser on 08/09/2011 at 12:49 PM


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