On Tue, 2 Apr 2002, Matthew Boeckman wrote:
> I'm running an ultra5, and trying to level0 a 60+gig filesystem. Using
> software compression took over 22 hours (i killed it at that point) so I
> decided to use hardware, specifying /dev/rmt/0cn as the tape device in
> amanda.conf. When I tried to run amdump, it failed saying that "dumps
> too large for disk", which is true if you don't count the hardware
> compression I was trying to use. The tapes are AIT2 50GB tapes. Is there
> a way to force amanda to do this? I assume perhaps amadmin csd force
> <diskname> ? I wanted to know for sure before kicking off another
> 20+hour backup cycle. Or is there something that I have to configure in
> amanda to let it know i'm using hardware compression and to ignore tape
> warnings?
Make sure that you configure the tape length in amanda.conf to specify
what you think it is that you'll be able to get on a tape counting
hardware compression.
When I used (note past tense) hardware compression with our systems, I was
using 40 GB DLT tapes. With regular, unzipped data I was getting close to
70 GB on a tape, so I set the tape length to 65000 Mb. It worked fine with
several partitions and combinations, anywhere from 45 to 65 GB in size.
Unfortunately, one particular partition, only 45-50 GB in size, was loaded
with small directories containing nothing but gzips. I was not able to get
that on a tape until I used GNUTAR to break it up.
I stopped using hardware compression because the general attitude among
the experts here was that amanda is better off doing her own packing. I
haven't really noticed a significant difference, but, as always, YMMV,
etc.
- - - - -
Eric Trager
