For fiber-attached tape drives - use snmp to monitor the fiber switch ports.

I use mrtg to acquire the data from my two tape-oriented SAN switches; this 
feeds my hobbit (renaming, currently, to xymon) monitoring package. I get to 
see the activity for each tape drive (one per switch port) and for each TSM HBA 
(one per switch port - zoned to all tape drives, run as one primary and 4 
alternates per switch).

The resulting graphs show that my fifth adapter to either switch from TSM us 
idle about 50% of the time, peaks at 400 MB/sec, and runs at a fairly steady 
200 MB/sec during my peak tape activity time. I'm running 10 LTO-4 and 6 LTO-2 
in a 3584 library -- 16 drives, 10 HBAs from TSM -- and it looks like I'm 
getting my money's worth.

Tom Kauffman
NIBCO, Inc

-----Original Message-----
From: ADSM: Dist Stor Manager [mailto:ADSM-L AT VM.MARIST DOT EDU] On Behalf Of 
David Bronder
Sent: Friday, February 27, 2009 3:34 AM
To: ADSM-L AT VM.MARIST DOT EDU
Subject: Tape performance (was: Re: Preferred TSM Platform)

Wanda Prather wrote:
>
> And there is NO instrumentation in Windows to give you any idea whatever
> about what is going on performance-wise on a bus with tape drives attached.

Unfortunately, there doesn't seem to be any real instrumentation in AIX
about tape drive performance, either.  None of the standard AIX tools
seem to give tape-related information (e.g. iostat or nmon), either for
the tape drives themselves or for the buses or adapters the drives are
connected to (unless there is also disk behind those buses or adapters).
(Speaking only of FC drives, since the last time I used SCSI tape drives
years ago, I never tried to get that data.)

So far, neither IBMers nor business partners I've talked to have been
able to identify a way of collecting that kind of data, either.  The best
ideas I've been able to come up with are manual timing tests (measure the
time to transfer a known volume of data, whether within TSM or externally)
or to look at stats on the fibre ports on the SAN switches (assuming one
has that kind of access to the switches).

If anyone can tell me differently, I'd love to hear about it.  Even if
(especially if?) it's something dead simple or obvious that I've been
missing.

=Dave  (sticking with AIX for TSM for the forseeable future)

--
Hello World.                                    David Bronder - Systems Admin
Segmentation Fault                                     ITS-SPA, Univ. of Iowa
Core dumped, disk trashed, quota filled, soda warm.   david-bronder AT uiowa 
DOT edu


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