We have been seeing something similar with out AIT3 drives running in a
Spectralogic 64K. Also almost exclusivly during reclamation processing . The
difference with our situation is in addition to read errors occationally the
volume will fail to unmout and remain stuck in the drive . We then have to
power cycle the drive to eject the tape. running scsi traces on the drives when
this issue comes up we have found that the event is always preceded by a scsi
forward command asking the drive firmware to move the tape position forward by
some increment. Sony has identified this as a firmware problem and is testing a
fixed version of code right now.
Craig Riley
The Children's Hospital in Denver
-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU]On Behalf Of
Steven Bridge
Sent: Friday, June 25, 2004 8:02 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: AIT drive I/O problems
Currently running TSM server version 5.1.8 on an AIX 5.2 machine.
We have a Qualstar TLS-412600 library with three AIT-2 drives.
We are having continual problems with I/O errors almost exclusively
during the reclamation of tapes. Most often 98-99% of the reclaim works
but we are seeing with perhaps quarter to a half of our reclaims a
number of read errors ( < 100 ). In almost all cases, when we then
perform a 'move data' on the errant tape, it reads the remaining data
off without any problems. Errors have been seen on two of the drives
over the past month - but I'm not sure about the relative frequency
of use of all 3 drives to determine whether the other drive is error
free or just lucky.
What is most frustrating about this problem, is that a drive
experiencing read errors then hangs. The reclaim process is cancelled
when the volume has no reads 'logged' for some time - but the process
usually takes between 4 to 12 hours to stop - presumably waiting on some
I/O timeout. The drive can be observed performing some activity during
this time - continual retries perhaps ? If we can't wait for 12 hours
for the drives to be available again, the whole AIX box has to be
reloaded to clear the situation.
Drives have been replaced following tape jams but the replacement
drives still exhibit the same problems.
We have set the drives up with a cleaning frequency of 1000 GB - so
they are being cleaned every now and then.
I would be interested to hear if anyone else has experienced the
same problems with these drives - assuming anyone else uses AIT drives.
I wonder whether the problem is symptomatic with these drives or
whether there are any firmware upgrades that might fix the problem.
How do you find out what version is on the drive ?
I would also be very interested in any suggestions for preventing the
interminable hangs. Is there anywhere that this timeout can be reduced ?
Examples of errors logged :
2004-06-24 15:12:14 ANR8302E I/O error on drive DRIVE0 (/dev/mt0) (OP=READ,
Error Number=7
8, CC=205, KEY=FF, ASC=FF, ASCQ=FF, SENSE=**NONE**, Description=SCSI adapter
failure). Ref
er to Appendix D in the 'Messages' manual for recommended action.
then eventually when the cancel process completes ;
2004-06-24 23:17:49 ANR8302E I/O error on drive DRIVE0 (/dev/mt0) (OP=FSR,
Error Number=78
, CC=205, KEY=FF, ASC=FF, ASCQ=FF, SENSE=**NONE**, Description=SCSI adapter
failure). Refe
r to Appendix D in the 'Messages' manual for recommended action.
+----------------------------------------------------------------------+
Steven Bridge Systems Group, Information Systems, EISD
University College London
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