Re: Client compression vs. Hardware Compression on Magstar

Hi Matt,

We have 3590 drives. The tapes hold 10GB uncompressed and 30GB compressed,
though I have a couple of tapes containing Oracle database backups with
50GB and over. Here's my best one:

A00334             TAPEOFFSITE  TLDS_3590    59,833.4  100.0    Full

Yes, that's 59.8GB on a single 10GB tape! We do not do ADSM client
compression. My average capacity rate across all full tapes (AIX, W95, and
WNT platforms; OS, DB, and user files) is 28GB. My worst tape, containing
mostly already compressed files from windows, is 9.5GB. From this, I think
IBM's claims of 3:1 are not "best case", but "average case", unlike all
the other vendors I know of...

Also, the 3590 drives are extremely fast. They seek to any spot on the
tape within 30-60 seconds, and have transfer rates that make hard drives
jealous.

Ours in a 3494 library and are pretty happy with the whole setup. We have
had a few trouble calls on the 3590 drives relating to load/unload
failures and write errors. These problems were eventually resolved by the
CE's.

Hope this helps,
-Scott
________________________________________________________________________
________________________________________________________________________
    L. Scott Emmons    | CableData R&D Center - El Dorado Hills, CA, USA
Staff Software Engineer|  Unix Administration, Systems Development Dept
    (916) 939-6088     |  Views and content are my own, not CableData's

>-----Original Message-----
>From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU]On Behalf Of
>Matt Cleland
>Sent: Wednesday, July 01, 1998 1:40 PM
>To: ADSM-L AT VM.MARIST DOT EDU
>Subject: Client compression vs. Hardware Compression on Magstar
>
>
>For those of you who are using IBM 3590 or 3570 tape drives, has
>anybody done comparisons between client compression and
>hardware compression in the drive?  IBM says that the Magstar
>drives can do up to 3:1 compression, which is pretty good.
>
>Thanks!
>
>--------------------------------------------------------------
>Matt Cleland                            mcleland AT msiinet DOT com
>Midland Systems, Inc.                   (618) 345-0864
>St. Louis, MO                           (618) 346-1779 FAX
>