>> On Mon, 24 Aug 2009 11:53:52 -0500, "Ochs, Duane" <Duane.Ochs AT QG DOT COM> 
>> said:

> I'm looking for some workable suggestions for larger lun backups.

> I'm talking 1.5tb and larger lun sizes. I have a number of remote
> sites that have large quantities of hi-res image files and they need
> an offsite backup solution. Usually we are notified before the disks
> go into production and the backups grow as the disk is populated.

> Normally not a big deal. Now we are in the middle of a large
> conversion for many remote sites which will require a full backup
> for all of the sites. And each has in excess of 6 tb of images. In
> addition we are also migrating a number of rogue sites to TSM which
> also have in excess of 4tb locally.

The critical point here is not 'Large Lun' but 'initial incremental'.
Instead of scanning 4TB of stuff, you want to _send_ 4TB; nearly
serially.

Putting disk on the write side of that is just silly, unless you have
an XIV.  (drool)

So you should be thinking in terms of direct write to tape.  A single
3592 will happily eat 80 MB/s of uncompressible data for as long as
you can keep the buffers filled.  That adds up to 3.mumble hours per
TB.

If you send two streams, you'll be able to eke out the rest of the
~112MB/s that a gig link will get you, at the cost of slowing down
each individual stream (i.e. they each go from approaching 80-mumble
to approaching 56-mumble MB)


> Some specifics: I have 3 TSM servers (AIX) with either a L700 or a
> T950 library.  No data is backed up locally. All data is sent over
> the network to a remote TSM server.

Drive technology?

- Allen S. Rout