Storage Virtualization – is there a point?

This has been bothering me for a while, and I think I’m not alone.

Hitachi has been making great progress with their virtualization gear, as has IBM, Falconstor before them, etc.

They claim you’ll be freed from the vendors’ shackles, achieve greater utilization of your arrays, simplify administration, cure cancer etc.

Well, here’s what I think:

  1. You will instead be shackled to the virtualization provider
  2. You won’t have a clue where your stuff is
  3. If you want to retire an array you could have problems (imagine creating a LUN composed of LUNs from 3 different arrays)
  4. You STILL have to use the management interfaces of the back-end arrays, since you still have to provision the storage. Instead of provisioning to hosts you provision to the virtualizer.


So, what have you gained, exactly?


2 Replies to “Storage Virtualization – is there a point?”

  1. FYI: HDS’s virtualization does not lock-in any storage array. If at any time you don’t want to virtualize the array any more, simply connect it back to the SAN and do a SCSI device search and reconnect the LUNs to the host. There is no special interpetation/formatting of LUNs or mapping tables.

    Also, virtualization of storage is not taking storage from several different arrays and putting it together into a single LUN. I’m not aware of any vendor recommending that scenario. Its not a good idea for several reasons.

    Virtualization is about enabling data to be migrated, copied, replicated across different arrays to help folks meet the needs of the applications or situations.


  2. Well, then stick to one vendor, and do all your migration, replication etc. without issues.

    I’m just leery of having all my data pass through one box. How does the USP deal with massive failure? A certain airline I used to work for had such a massive failure, so the box can break (as can anything else).

    Connecting everything through it may be ill-advised.

    I’m the least luddite-like person you’re ever likely to meet. I love technology but you need to also be practical.

    The selling points for virtualization that I’ve seen from vendors are the ones that I addressed. There are other ways to do migrations, and an out-of-band approach such as EMC’s Invista (currently infantile) may be the better idea.


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