vSphere Storage Appliance Overview


When VMware announced vSphere 5 they mentioned a new storage appliance called VSA or vSphere Storage Appliance (VSA).  It is intended to be used by smaller VMware environments who don’t/didn’t have a SAN or NAS array at their disposal. You know, because SAN’s are expensive, complex and such. Prior to this you could still deploy vSphere but you were heavily limited on the things that made vSphere so cool; vMotion, and HA for example.

That Sounds Nifty, how does that work?

It simply makes use of your server’s internal hard drives as a pooled shared resourced, pretty simple really.

Here is some more detail. For every ESXi server you will have a VSA deployed to it as a virtual machine. Making use of the available of the local disk (those hard drives that came with your server) on the ESXi host and it will pool these together and provide a replicated NFS volume for the ESXi server.  Once you do this on several hosts, then you should have a highly resilient storage backup system, since it will replicate these across all of the hosts providing a clustered and shared data store across all of your hosts.  Make sense?

Why I like it:

  •  Easy set-up, 5+ clicks and you are good to go, supposedly done in less that 10 minutes
  • Managed from vCenter, which is nice (doesn’t depend on vCenter to stay active, so you are safe if vCenter crashes)
  • Help lower CapEx and OpEx for your IT department, this is huge!
  • Because it uses Network Mirror and local RAID it is really robust with little investment on your part
  • Some rather unique custom settings: RAID 10, RAID 1, replacement of Node in case of failure.

 So does this mean you can kick EMC and NetApp to the curb?

Sorry not yet, keep writing those big checks but it will help in a variety of different scenarios.

Any remote location or branch office where you used to put a small SAN is a perfect example. Just simply beef up the hard drives on your servers and use those hosts as pooled storage.

Lab Environments are literately perfect for this. Now instead of waiting for some ancient hardware to come your way or beg management for a little money you can have a fully functioning SAN in your environment.

Very Small environments work great too, but just know this isn’t a permanent solution as of yet and wouldn’t replace a fully robust storage platform.


  • This is version 1 which means that while they claim it is 99.9% availability there isn’t any guarantees, and there may be some bugs
  • There is a limited list of compatible hardware
  • It doesn’t scale too well. Only supporting three virtualized hosts per instance
  • JBOD or external disk isn’t supported. Only Internal, I believe this is due to the RAID card built into the physical server hence why it needs to be on the HW compatibility list
  • Disk Capacity and VSA-Node count cannot be changed after set-up
  • Only vSphere 5 or later will support it at this time
  • Doesn’t support non VMware Machines…as in Hyper-V or Citrix
  • You need at least 2 nodes to make it work, so you will need at least 2 servers
  • Since it is replicated data, eats up space quickly on each server
  • Haven’t seen the performance numbers, but there will be some overhead and could limit the density of your server farm
  • Lastly, it is only local backup and won’t solve geographic disaster recovery

Big Picture:

This isn’t really a new idea, virtual iSCSI appliances have been around awhile and network RAID isn’t new either, LeftHand. But what it is doing is removing external needs for a VMware environment. By taking away the need for a 3rd party storage device it shortens the deployment time for your virtual environment. I highly doubt that this is the last involvement that VMware will have with storage and see them providing much more significant tools for managing your virtual information.  More to come.

For a Technical indepth view, take a look at this link.