Barry -- what level of software compression are you using?  Orbit has told
us to NOT use '2' or more, but to use '1' plus hardware compression.  Our
drives are configured as C1521B's as well, and I know that we got much
better throughput when using compression level '2' and no hardware
compression.  We have to manually disable compression on our DLT's, because
DEVCTRL won't toggle that properly.  EJECT and LOAD parms work just fine.

Lee Gunter          [log in to unmask]




From: [log in to unmask] on 09/09/98 01:49 PM

Please respond to [log in to unmask]


To:   [log in to unmask]
cc:    (bcc: Lee Gunter/BCBSO/TBG)
Subject:  NON HP DLT




A few weeks back I posed a question about placing a non-HP DLT on an
HP3000/959-400.  This past weekend I configured it in as a HPC1521B and
hooked
it up.   This is a DLT4000 (unknown what manufacturer).   The only problem
I ran
across was when I attempted to use DEVCTRL to disable hardware compression.
On
our DDS2 tape which had hardware compression we disabled hardware
compression
because we were using software compression (Orbit Backup3000+).  With the
DLT
disabling hardware compression does not seem to be necessary.

Here are some of the performance stats that I have come up with:

A full backup of 19M sectors took 7 hours and 4 tapes with a DDS2 drive.  A
full
backup with the DLT took 3 hours and 1 tape.

A backup on 371MB took 8min and 52sec with software compression.
A backup on 371MB took 11min and 21sec without software compression.

If anyone has any questions please feel free to ask!


----------------------------------------------------------------
Barry Durand
[log in to unmask]
----------------------------------------------------------------