On Friday 27 February 2009, David Bronder wrote:
> 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.
The problem is that the numbers are not available.  Don't ask me why.

What I do is starting nmon.  With 'a' you can see the adapter stats.  With 'V'
you van see the volume group stats.  The difference is tape drive I/O.


Stef