sar and syslog.log messages

[ITeam]

We have an L-class server running 11i and experiencing some strange behaviour. The backup to a DLT drive is taking 2 to 3 times longer than normal. Upon checking system logs, GSP logs etc I found no error messages reported pertaining to the tape drive or SCSI controllers. Checked the sar logs for disk devices and found no excesive disk usage. Checked the sar logs for cpu usage and found that the %wio was almost constanlty at 100%, occasionally decreasing for %user and %sys to have cpu time.
I suspect the problem is lying with either the tape drive itself, cable/termination or the SCSI controller the tape drive is attached to.
The syslog.log is constantly displaying the following.
Line 4867 in /ux/core/kern/common/io/pat_psm.c: pat_get_olar_info - rc -1 slot_id -16056443
I'm not sure if this is related to the problems we are experiencing or not. If not, does any one have any suggestions as to the reason why this message is being produced.
Many thanks in advance, Graeme.

[V.Tamilvanan]

Hi,
The error is related with PDC Firmware install the patch PHSS_25685 (or superseeding) to flash the PDC.

See the below link for more details:-
http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=69038

[Bharat Katkar]

For increased backup time I would suggest you to check for memory and then disk bottleneck.
This seems to be an performance issue.
See the attached file for reference.

[ITeam]

sar -d doesn't report any excessive disk usage. sar -w shows no swapping occuring at all. Any further suggestions.

[Bharat Katkar]

I would suggest u to analyze in this specific order:
1. Buffers # sar -b
2. Memory # vmstat -n
3. Disk # iostat
# sar -d

If you fine tune the System at Buffer/Memory level your i/o problem may go away.

[Shaikh Imran]

Hi,
The problem seems to be with the DLT drive hardware.If possible pls try replacing it and test.This is the best way to confirm the problem.I have faced this but my case was having a library so i could confirm with the other drive.

Regards