I am having a tough time recovering data from a tape.This is the first
time since I started using compression. I can dig through my
amanda.conf, the amdump file for the run, the log file, if that
contains the info I need. I am running Amanda 2.4.2 and I'm using an
Exabyte 8500 tape drive. I back up two machines one an older RedHat
(6.2) which has the tape in it, and a RaQ Cobalt server. I built
amanda from source on both machines, and I believe my problem is
somehow skipping over the headers, so the gzip program will extract
the data. But I'm despearate and will defer to experts.
I can position it to a file but I can't quite read it. It is almost
like the header info can't be stripped off the begginning. I have been
repositioning it with mt and checking the status so that I'm always
starting at block 0 and partition 0 of whatever file I'm trying to
grab off the tape. Compounding my aggrevation is that I did manage to
use the command sequence to successfully pipe the first file (a back
up of the partion /var on a remote host) to the tar command -- but I
seem unable to repeat it. I've looked through my command history and
can't find anything unique so all I can assume is that somehow I
either have damaged the tape or can't quite get to the right position
do to miscalculation or block size error. I have the usual locating
option with mt: fsf,fsfm,fsr,asf,bsf,bsfm, and bsr.
The dd command is perfectly capable of dumping the files, but I don't
really have the space of my amanda server machine. I need to restore a
user directory /home/user/x on a remote host. I figure it would be
easier to restore the directory to the machine with the tape drive and
go from there, but for now I'm stuck.
====================================================================
[root@omaha /whatever]# mt -f /dev/nst0 status
SCSI 2 tape drive:
File number=4, block number=0, partition=0.
Tape block size 1024 bytes. Density code 0x0 (default).
Soft error count since last status=0
General status bits on (81010000):
EOF ONLINE IM_REP_EN
[root@omaha /whatever]# dd if=/dev/nst0 bs=32k | head -4
AMANDA: FILE 20030512 omaha / lev 0 comp .gz program /bin/gtar
To restore, position tape at start of file and run:
dd if=<tape> bs=32k skip=1 | /bin/gzip -dc | bin/gtar -f... -
[root@omaha /whatever]# dd if=/dev/nst0 bs=32k skip=1 | /bin/gzip -dc
| /bin/gtar -tf -
gzip: stdin: not in gzip format
2+0 records in
1+0 records out
Broken pipe
====================================================================
Even when I tried to position from the beginning of the tape:
====================================================================
[root@omaha /whatever]# mt -f /dev/nst0 asf 0status
[root@omaha /whatever]# mt -f /dev/nst0 status
SCSI 2 tape drive:
File number=0, block number=0, partition=0.
Tape block size 1024 bytes. Density code 0x0 (default).
Soft error count since last status=0
General status bits on (41010000):
BOT ONLINE IM_REP_EN
[root@omaha /whatever]# dd if=/dev/nst0 bs=32k skip=1 | /bin/gzip -dc
| /bin/gtar -tf -
gzip: stdin: not in gzip format
1+0 records in
1+0 records out
====================================================================
--
Josh Kuperman
josh AT saratoga.lib.ny DOT us
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