Greetings,
We have a TSM instance that serves as the library master for two
tape libraries. One is a IBM3584 tape library with 24 LTO4 drives. The
second is a virtual tape library, an EMC EDL configured as a IBM3584
with 128 LTO1 tape drives. The library master has 9 other TSM instances
and 4 Lan-free clients that are library clients, and appeal to it for
tape mounts. Most of the time this works just fine.
All the TSM instances are running TSM 5.4.3.0. A few weeks ago we
upgraded them from 5.4.2.0 in order to pick up a patch to provide the
LIBSHRTIMEOUT parameter. This may not have anything to do with our
problem, but it IS a recent change.
The problem comes when we have any problem with the real IBM3584
tape library. Two weeks ago a tape got stuck in the gripper. Last week
the gripper itself actually broke, so no tapes could get mounted. Last
night it was a single tape drive that got an error and went Polling.
For some reason, in each one of these cases, after an hour or two all
tape mounts start hanging, even those belonging to the virtual tape
library. When we would do a 'q mount' they all showed up in Reserved
status. So before long all backups going to the virtual tape library
ground to a halt.
Can any of you see a reason why the TSM library master should get
into such a problem? Shouldn't all tape mounts be asynchronous? It
seems like to me a single tape drive getting into problems should not
keep all other mounts from proceeding. And it doesn't happen instantly.
It seems to happen gradually.
I probably should also mention that this is a fairly busy
environment during the night. It isn't unusual for us to have over 100
virtual tape mounts simultaneously. That is the reason we needed the
LIBSHRTIMEOUT parameter (mentioned above). Before we had that, we
sometimes would get timeouts that caused tape mount failures, because
the TSM library master's queue of tape mounts polls would get overrun.
Since we put on that patch, and added 'LIBSHRTIMEOUT 60' to the options
file, that problem has gone away. But now this problem seems to have
taken it's place.
Best Regards,
John D. Schneider
Lead Systems Administrator - Storage
Sisters of Mercy Health Systems
3637 South Geyer Road
St. Louis, MO 63127
Phone: 314-364-3150
Cell: 314-750-8721
Email: [EMAIL PROTECTED]
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