As I've discussed in prior postings, bacula sometimes cannot read a tape after
my
VXA-320 packetloader autochanger changes tapes in the middle of a backup job.
I
would sometimes have to manually unmount and then mount the tape in order to
get the
job to continue. So with help from others on this list I heavily modified the
mtx-changer script so it uses btape to attempt to read the bacula label on the
tape
after loading it. If btape cannot read the label, then the script unloads and
loads
the tape and tries again. My assumption is that if btape cannot read the label,
then
bacula won't be able to either.
After a couple months of use in production I finally have captured this event
completely in a log file (I have also enhanced logging in the mtx-changer
script to
make it easier to see what is happening). Note that a tape was loaded, btape
was
unable to read the label, it was unloaded and loaded again, then btape was able
to
read the label and the backup job continued. The best part is that I was on
vacation
when this happened, so it saved a backup that would otherwise have failed.
Of course, this is not a fix for the problem. It only improves the chance of a
successful backup. Now with this complete log, I would appreciate any ideas
you may
have on what the actual problem is and how to fix it so this is not necessary.
Thanks,
Mark Nienberg
20080906-02:50:22 ---Started with Parms: /dev/sg3 load 8 /dev/nst0 0
20080906-02:50:22 Doing libTool /dev/sg3 -m s8 d1
20080906-02:50:45 libTool load returned 0
20080906-02:50:45 entered wait_for_drive
20080906-02:50:55 33 sec - mt status for /dev/nst0 returned IM_REP_EN
20080906-02:51:05 43 sec - mt status for /dev/nst0 returned IM_REP_EN
20080906-02:51:15 53 sec - mt status for /dev/nst0 returned IM_REP_EN
20080906-02:51:25 63 sec - mt status for /dev/nst0 returned BOT ONLINE
IM_REP_EN
20080906-02:51:26 The full mt status after final check is:
20080906-02:51:26 SCSI 2 tape drive:
File number=0, block number=0, partition=0.
Tape block size 0 bytes. Density code 0x82 (DLT 20GB uncompressed).
Soft error count since last status=0
General status bits on (41010000):
BOT ONLINE IM_REP_EN
20080906-02:51:26 Waiting 30 sec for good measure
20080906-02:51:56 Elapsed time from start to drive ready: 94 sec
20080906-02:51:56 Attempting to read bacula label on tape in drive
20080906-02:51:56 ---Started with Parms: /dev/sg3 loaded 0 /dev/nst0 0
20080906-02:51:56 Doing mtx -f /dev/sg3 status -- to find what is loaded
20080906-02:51:56 could not read bacula label on this tape
20080906-02:51:56 the btape output from the read attempt was...
Tape block granularity is 1024 bytes.
btape: butil.c:285 Using device: "/dev/nst0" for writing.
06-Sep 02:51 btape JobId 0: 3301 Issuing autochanger "loaded? drive 0" command.
06-Sep 02:51 btape JobId 0: 3302 Autochanger "loaded? drive 0", result is Slot
8.
btape: btape.c:372 open device "VXA3drive" (/dev/nst0): OK
*06-Sep 02:51 btape JobId 0: Error: block.c:999 Read error on fd=3 at file:blk
0:0 on
device "VXA3drive" (/dev
/nst0). ERR=Input/output error.
btape: btape.c:422 Volume has no label.
Volume Label:
Id : **error**VerNo : 0
VolName :
PrevVolName :
VolFile : 0
LabelType : Unknown 0
LabelSize : 0
PoolName :
MediaType :
PoolType :
HostName :
Date label written: -4712-01-01 at 00:00
*
20080906-02:51:56 no label, so load did not succeed, unload and try again
20080906-02:51:56 Doing libTool /dev/sg3 -m d1 s8
20080906-02:52:38 Doing libTool /dev/sg3 -m s8 d1
20080906-02:52:59 libTool load returned 0
20080906-02:52:59 entered wait_for_drive
20080906-02:53:09 167 sec - mt status for /dev/nst0 returned IM_REP_EN
20080906-02:53:19 177 sec - mt status for /dev/nst0 returned BOT ONLINE
IM_REP_EN
20080906-02:53:19 The full mt status after final check is:
20080906-02:53:19 SCSI 2 tape drive:
File number=0, block number=0, partition=0.
Tape block size 0 bytes. Density code 0x82 (DLT 20GB uncompressed).
Soft error count since last status=0
General status bits on (41010000):
BOT ONLINE IM_REP_EN
20080906-02:53:19 Waiting 30 sec for good measure
20080906-02:53:49 Elapsed time from start to drive ready: 207 sec
20080906-02:53:49 Attempting to read bacula label on tape in drive
20080906-02:53:49 ---Started with Parms: /dev/sg3 loaded 0 /dev/nst0 0
20080906-02:53:49 Doing mtx -f /dev/sg3 status -- to find what is loaded
20080906-02:54:01 read bacula label B0000001
20080906-02:54:01 read label, so second load succeeded
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