* Networker 7.5.1 (Sun) server on Solaris 9/SPARC
* Two libraries with six SuperDLT 320 drives in each,
all SCSI-attached; slowness is on one library only
* Most of the clients involved are Solaris 8, 9 and 10, all
SPARC, as well as a couple of Windows clients
The last couple of nights I've seen two different drive/tape combinations
produce _EXTREMELY_ slow writes, but completely without error as far as I
can tell. Once a tape is loaded in the drive it backs up, but at rates
generally less than 20KB/sec per saveset. There are no errors in the
daemon.log, none in /var/adm/messages, 'iostat -En' shows nothing wrong,
'netstat -i 2' shows no collisions, etc. So far it's happened with one
tape in one drive and a different tape in another over the last two backup
runs.
Interesting thing on one (only) of these clients...
Since this client is a critical system with limited backup downtime, I
actually killed its final 'savepnpc' process after it crawled for 6.5
hours since the customers needed their apps up. When I did so Networker
tried again _to_the_same_tape/drive_ and saved the filesystem in the
typical 4 minutes or so - Full normal speed, in other words. Then again,
the next backup session, that same saveset finished, but took almost two
hours (on a different tape/drive). Once again, 3-5 minutes is typical.
There were three other systems on the same tape/drive, so I killed
savepnpc on each of them, hoping for similar results. They all restarted
but no faster than before.
I patched the backup server (Solaris recommended cluster) last Wednesday
afternoon; everything was fine that night and Thursday night, with the
first issue showing up during Friday night's backups. There have been no
changes other than the patch cluster.
I was thinking maybe a particular nsrmmd instance might get slow, but that
doesn't fit with the speedy backup after the retry. Other than the saveset
I mentioned above, it's all been different clients/savesets each time. No
pattern other than all being on one library (one that's usually the least
troublesome, naturally).
Anyone run ever into this? I have a feeling if this continues, it will be
a troubleshooting nightmare... :-\
Thanks!
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