[Veritas-bu] My tapes get FULL status with less than minimum capacity

Since your drives support hardware compression, you should turn off software 
compression.  Check that the dip switches are set correctly on the drives.  You 
didn't mention your server platform, but on a Solaris master for example, to 
get the best tape utilization you want to make sure that your st.conf settings 
match the drive firmware level.  On a Windows platform, I'd be willing to bet 
that the firmware level is tied to the driver version...

Neil

-----Original Message-----
From: Louis-Luc Le Guerrier [mailto:leguerri AT Canr.Hydro.Qc DOT Ca]
Sent: Wednesday, March 03, 2004 11:16 AM
To: veritas-bu AT mailman.eng.auburn DOT edu
Subject: [Veritas-bu] My tapes get FULL status with less than minimum
capacity


Hello,
I'm using Veritas NetBackup 4.5 FP3, and 35GB AIT-1 Sony
tapes. It's stated native 35GB and compressed up to 91GB.
Therefore, one would expect tapes won't get FULL status
until they fit at least 35 * 1024 * 1024 KB, so 36,700,160
KBytes. I'm using client compression, and the tapes get
FULL status from 35,xxx,xxx Kbytes to 42,xxx,xxx KB, very
rarely over 40,000,000 but sometimes one does get that high. I 
tolerate 35,000,000 KB and up since volume headers
should take space. 
However, as time goes by, and tapes cycle, I often get lower
fills of 34,xxx,xxx and 33,xxx,xxx KBs, and more recently
some in the 32s.

One more strange thing is that when a tape is full of data
from Windows 2000 client, the situation is even worse, even
on a BRAND NEW tape! Last week-end I backed up 2 Windows
2000 servers onto 4 tapes, and all 4 got low fills of
31,xxx,xxx KB and the lowest one being 30,125,920 KBs!
With UNIX data, fillings are better, but not as good as
they used to be. All our UNIX and Windows classes use
compression

Does anyone know what happens in general? 

Can Win2000 data be so tightly
compressed already that client compression should be removed
to obtain an uncompressed true 35GB?

Thanks for any enlightning on this mystery.

Luc

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