On Wed, Jan 18, 2006 at 08:44:36AM -0600, briandiven AT northwesternmutual DOT 
com wrote:
> Has anyone looked at the MAID (Massive Arrays of Idle Disk) solution
> from Copan?  They have been marketing it as a replacement for tape and
> as a pseudo-VTL.  This looks like not much more than just another disk
> (JBOD) to be used in a D2D pool.

I believe it's bit more than JBOD.  There are a couple of players in
this space (I think the Petabox is another).  Essentially what these
boxes do is to spin up only 10% or so of the drives at any one time.
When you think of how you would use the disk, this makes perfectly good
sense.  You write your incrementals to disk, and then likely don't use
it until you write over them again (or at least use them infrequently).
If you need to do a restore, the disk library automatically spins up the
right disk and makes it available.  I think that operation takes about 2
minutes or so which would be comparable to a tape mount.  The reads,
however, would be much faster.  You then spin the disk back down again.

Since only 10% of the drives are spinning at any one time, you save a
*ton* of power and cooling costs.

        .../Ed

-- 
Ed Wilts, Mounds View, MN, USA
mailto:ewilts AT ewilts DOT org