Gilbert,

Is there a particular reason you have such a large library with just two
drives?  I have a 3583 with four drives.  I did that to prevent the very
problem you're reporting.

Assuming it hosts a primary storage pool, you will need two drives for
reclamation unless you use a FILE devclass disk pool as a reclaim pool.
Then you can turn one two-drive process into two one-drive processes with
a buffer in between them.

If you also might be doing reclamation of your copypool(s) - a situation I
sometimes see on my system - you will need a third drive.

A fourth drive reserves one drive for "outgoing" data to clients.  That is
why I put four drives in all four of my tape libraries.

My 3583 connected HV Diff SCSI gives a sustained 12 MB/s per drive.  That
works out to about 43 GB/hour minus "bubbles" from when the tape is being
repositioned.

Tab Trepagnier
TSM Administrator
Laitram Corporation






Guillaume Gilbert <guillaume.gilbert AT DESJARDINS DOT COM>
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
07/03/2002 08:40 AM
Please respond to "ADSM: Dist Stor Manager"


        To:     ADSM-L AT VM.MARIST DOT EDU
        cc:
        Subject:        Reclaiminig LTO Tapes


Hey there

Maybe its because I'm used to using STK 9840 tapes but yesterday I saw an
LTO tape at 25 % utilisation take almost 4 hours to reclaim, which to me
is awful. How am I
supposed to reclaim my tapes with that kind of performance?. The drives I
use are IBM Ultriums in a 3584 library. With only 2 drives it makes it
hard for users to do
restores...

Are there any options I can change to make this go a bit faster. I know
the start/stop on LTO's isn't good.

Thanks for the help.

Guillaume Gilbert
CGI Canada