Diggin' technology every day

December 2, 2011

New record holder for inefficient storage – VMware VSA

Filed under: Security — Tags: , — Nate @ 11:15 am

I came across this article last night and was honestly pretty shocked, it talks about the limitations of the new VMware Virtual Storage Appliance that was released along side vSphere 5. I think it is the second VSA to receive full VMware certification after the HP/Lefthand P4000.

The article states

Plus, this capacity will be limited by a 75% storage overhead requirement for RAID data protection. Thus, a VSA consisting of eight 2 TBs would have a raw capacity of 16 TB, but the 75% redundancy overhead would result in a maximum usable capacity of 4 TB.

VMware documentation cites high availability as the reason behind VSA’s capacity limitations: “The VSA cluster requires RAID10 virtual disks created from the physical disks, and the vSphere Storage Appliance uses RAID1 to maintain the VSA datastores’ replicas,” resulting in effective capacity of just 25% of the total physical hard disk capacity.

That’s pretty pathetic! Some folks bang on NetApp for being inefficient in space, I’ve ragged on a couple of other folks for the same, but this VSA sets a new standard. Well there is this NEC system with 6%, though in NEC’s case that was by choice. The current VSA architecture forces the low utilization on you whether you want it or not.

I don’t doubt that VMware released the VSA “because they could”, I’m sure they designed it primarily for their field reps to show off the shared storage abilities of vSphere from laptops and stuff like that (that was their main use of the Lefthand VSA when it first came out at least), given how crippled the VSA is(it doesn’t stop at low utilization see the article for more), I can’t imagine anyone wanting to use it – at any price.

The HP Lefthand VSA seems like a much better approach – it’s more flexible, has more fault tolerance options, and appears to have an entry level price of about half that of the VMware VSA.

The only thing less efficient that I have come across is utilization in Amazon EC2 – where disk utilization rates in the low single digits are very common due to the broken cookie cutter design of the system.

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