Hi All,
and special thanks to Norman
I'd like to explain our problem.
Our problem has nothing to do with slow allocation.
What makes us worried is unpredictable, very low data xfer rates from time
to time.
Before migration to VTS we used STK/Timberline ESCON devices.
Most of the devices had a dedicated escon channel each, so that,
once allocation succeeded, the throuput/performence was fantastic.
Now we have 4 local VTCs and 4 remote VTCs connected in a P2P VTS.
The allocation algorithm for logical devices is not documented in technical
literature and even IBM local engineers are not familiar with it.
We found an article in MIA books talking about putting OAM first in order.
When we tested the preference option we found out that it didn't work and
suspected that it occured because of the wrong order between the 2
subsystems.
The answer we got from CA related to options and capabilities of MIA
without mentioning 'VTS' or ordering possibilities.
Our major problem today is unpredictable elapse time depending on
lucky/bad combinations of allocations.
Some backup works that used to finish within an hour, in previous
configuration,
might take 5 hours today (if 2 concurrent outfiles are allocated on same
VTC
with 1 or 2 other pre-allocated files).
I want to be sure that prefernce and elimination options work well with VTS.
If it does, maybe the best solution is to assign highest priority to all the
devices of the vtc, on which the number of allocated devices is minimal ?
Does any one of you know of a similar-logic sources for relevant exits ?
I'm addressing the above questions (and coming too) to all of you but
especially to you, Norman.
We would like to use use different Esoteric names we defined for diferent
aspects of logical devices, but we don't know how ?
IBM's personal here rejected this possibility and claimed that it can't be
done because of SMS behaviour.
Regards,
Hanan Hassan
Systems - z/OS Technical Support
Mehish, 15 Lincoln, 67134 Tel-Aviv, Israel
ph: +972-3-5634352, fx: +972-3-5623717
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