Set your estimated capacity back to 39GB (higher if you KNOW you will get
more data on the tape). As the tape fills you will see the percent util go
up to 100%, the volume status of the tape stays as 'filling' until the tape
is physically full and the estimated capacity numbers will continue to
increase (matching the amount of data) as the tape fills.

Tapes in 'filling' status will mounted and filled in onsite pools. Tapes
that are offsite and 'filling' will reclaim but the numbers are bogus. I
check my copypool tape for 'filling' status daily and do a manual cleanup
whenever.

-----Original Message-----
From: Rob Schroeder [mailto:robs AT FAMOUSFOOTWEAR DOT COM]
Sent: Monday, October 28, 2002 5:48 PM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: 3590 compression vs tsm compression


Win2k SP2 client 4.2.1.32
Win2k Sp2 server 4.1.6 (Iknow  I know)

Here is my dilemma:  I have been setting the size of my 3590E device class
to 39 Gig (just under the 40 gig size limit) and have been doing
compression within TSM.  However, due to the number of clients and the
server size, I would like to have the hardware do more of the compression
to alleviate the processor bottlenecks I have.  Therefore I have tested
changing the tape capacity to 120G and turning off TSM compression.  If the
tape gets less than ideal compression (assume none) then when the tapes get
33% full and thus TSM lists the tape as filling.  The backups still think
there is no more room in the storage pool.  I am then left with these
situations:

1.  TSM must mount the tape before it recognizes there is no more room.
Obviously this is bad if there are 100 tapes and it takes 2 minutes per
tape to mount.

2.  TSM reclamation thresholds are shot because it wants to reclaim at 50%
utilization but will never get there because it can only go as high as 33%.

3.  My operators think that there is lots of room in the storage pool
because there are 100 tapes at 33% utilization leaving most of the tape
available, and they don't add tapes even though they are needed.

Do I need to continue to use software compression and forget about the
hardware side?

Any thoughts would be helpful.

Rob Schroeder
Famous Footwear
608-827-3495 phone
608-662-6495 fax