Robin,

I selected the threads of the DSMSERV process with glance using option "G".

All threads were listed (3 pages). If you use the "+" and go to the last
page you may be able to see some waiting on I/O. These are more than likely
the Tape threads. When active doing MIGRATION or BACKUP STORAGE POOL these
consume high amounts of CPU, SPACE RECLAMATION and MOVE DATA will also but
it depends on the density of the data on the tape.

I was able to compare a couple of ways, I regressed the driver back to stape
for all my tape drives except 1 and can show the high CPU. I also still have
a 4.2.3.2 system around and a test system I can configure and play with.

Bill Slaughter
Tupperware
407-826-4580


-----Original Message-----
From: Robin Sharpe [mailto:Robin_Sharpe AT BERLEX DOT COM]
Sent: Wednesday, October 15, 2003 8:53 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Re: High CPU Consumption on Tape Threads in DSMSERV

Bill,

We have a similar environment -- TSM 5.1.7.x, HP-UX (11i), DLT8000s and
LTO2's.  I have not noticed the increase you describe, but we have also
moved from an 2-CPU L2000 server to an 8-CPU rp7410.  Can you be more
specific about how you tracked that info with glance?  I'll be happy to run
the same tests and post my results.  Hoe did you test the stape driver?
With TSM 5.1.7.2, or are you comparing to the "old" config?  Or stand-alone
drives?

Regards
Robin Sharpe
Berlex Pharmaceuticals


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I have just had a call escalated to level 2 and was wondering if anybody
else is having a problem and may not know it. I was told I was the first to
report it.



We have recently upgraded to TSM 5.1.7.2 and noticed there is a higher
amount of CPU being consumed by the DSMSERV process. We were upgrading from
4.2.3.2.



I have narrowed it down using HP-UX glance to be related to tape drive
activity and can see (using glance) that there is a correlation between the
number of active tape drives and the amount of CPU being consumed. I
further
investigated and discovered there are many threads consuming CPU when this
happens and that 1 thread per Tape DRIVE is 90-100% CPU.



I compared these to the HP-UX stape device driver and it will only use 5 -
7% CPU (And it performs much faster).



Misery loves company; I would like to know if anybody else is experiencing
any of the same problems with high CPU on tape threads and what flavor of
UNIX they are using.



Bill





My Environment:

TSM Server 5.1.7.2

TSM Device Driver 5.1.7.2 and 5.1.6.5

HP V2500 32 CPU - HP-UX 11.0

STK 9710 DLT7000 (8 Drives)

STK 9710 DLT7000 (6 Drives)





Bill Slaughter

Tupperware

407-826-4580