Hi,

I am using Amanda to back up 4 machines to a 20/40 DDS4 (DAT)
tape in one of the machines. I am doing a full backup every
night as there is not a lot of data on all of the machines (they
are application servers, with not much data storage). As always
the backup size increases over time. Up until recently
everything has been going fine. Now I am getting errors that
there is "no space left on device" when writing to tape. The
thing that i am struggling to work out is why ? I am using
software compression and Amanda reports that after compression,
the output size is just over 15 GB (which should fit easily on a
20GB tape).

To further add to the confusion, I ran a "tapetype" to see what
Amanda thought it could fit on the tape drive and the results it
came back with were:

define tapetype testdds4 {
    comment "just produced by tapetype program"
    length 13565 mbytes
    filemark 0 kbytes
    speed 1842 kps
}

which shows that Amanda thinks the tapes are only 13.5 GB (or
thereabouts). This explains why the backup might be failing once
it goes over this value.

When I installed Amanda, I read the doc that says that hardware
compression is BAD and so should be turned off. The drive I have
doesn't have any jumper settings for compression, so I can't
turn it off there. I have never explicitly turned hardware
compression ON with the software, so I kinda assumed that it
wouldn't be doing hardware compression at all. From digging
through the archives there appears to be evidence of the same
happening to other people to support this theory.

So my question are:

1. Is my diagnosis correct (tape drive is using hardware
compression) ?
2. How can I tell if the drive is doing hardware compression ?
3. How can I stop the drive from doing HW compression ?
4. If this isn't the problem, I'm open to other suggestions.


Many thanks,
Tony.

=====================================

These dumps were to tape daily01wed.
*** A TAPE ERROR OCCURRED: [[writing file: No space left on
device]].
Some dumps may have been left in the holding disk.
Run amflush to flush them to tape.
The next tape Amanda expects to use is: daily04mon.

FAILURE AND STRANGE DUMP SUMMARY:
  wonderwoma /var lev 0 STRANGE
  qtechwas0  /var lev 0 STRANGE
  qtechwas1  /opt lev 0 STRANGE
  qtechwas2  /opt lev 0 FAILED [out of tape]


STATISTICS:
                          Total       Full      Daily
                        --------   --------   --------
Estimate Time (hrs:min)    0:03
Run Time (hrs:min)         3:12
Dump Time (hrs:min)        2:20       2:20       0:00
Output Size (meg)       15366.2    15366.2        0.0
Original Size (meg)     25498.3    25498.3        0.0
Avg Compressed Size (%)    60.3       60.3        -- 
Filesystems Dumped           29         29          0
Avg Dump Rate (k/s)      1878.7     1878.7        -- 

Tape Time (hrs:min)        1:45       1:45       0:00
Tape Size (meg)         11753.6    11753.6        0.0
Tape Used (%)              59.0       59.0        0.0
Filesystems Taped            28         28          0
Avg Tp Write Rate (k/s)  1909.3     1909.3        -- 


NOTES:
  taper: tape daily01wed kb 14775776 fm 29 writing file: No
space left on device
  driver: going into degraded mode because of tape error.



________________________________________________________________________
Want to chat instantly with your online friends?  Get the FREE Yahoo!
Messenger http://mail.messenger.yahoo.co.uk