Hello,
Matthias F. Brandstetter wrote:
Hi all,
I have a problem with bacula and some SLR tapes. My server has an "TANDBERG
SLR100" SCSI tape drive, which is capable of storing 50GB or 100GB
(compressed) onto SLR tapes.
I have about 50GB+ data to save, so I want to use tape drive compression.
First, I used an "old" tape to store those 50GB+ onto it, and it worked
like a charm.
Now I have a bunch of newly bought SLR tapes, but there I get an "out of
space" error, it seems those new tapes can't save compressed data (= more
than 50GB). I have not much experience with this tape drives, so please
help me with this questions:
How can I force hardware compression?
Are there some types of tapes which aren't ready for hardware compression?
Not that I knew.
I suggest you do the following:
- Unmount the tape drive you use from bacula, so you can access it with
other programs.
- Load a new tape, wait till the drive is ready.
- use tapeinfo or mt to check the compression status. It should be off
if compression being not set really is your problem.
- if not set, enable compression using mt.
- write some stuff to the tape, for example using dd.
- unload the tape, reload it.
- again, check compression status. It should now be on.
- rewind the tape (although it should be by now), write two EOFs onto it.
- label the tape with bacula and use it. See how much data fits onto it.
Thanks for any info, I am somewhat lost here :(
Three important points to notice: Once a tape is used, you can only
change compression before you write to it's beginning, i.e. right after
it's loaded. Fast forwarding and appending will probably not result in
writing compressed data, I guess - compression status is determined when
logging the tape into the drive.
Depending on your OS and software setup, there might be tools or
settings to allow setting the default tape compression status.
Compression works only with data that can be compressed; especially
stuff like digital video, mp3s, and other pre-compressed data will in
many cases expand rather than shrink when written with compression enabled.
Arno
Greetings and TIA, Matthias
--
IT-Service Lehmann [EMAIL PROTECTED]
Arno Lehmann http://www.its-lehmann.de
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