Jon Backus asks:
 
>Subject:      Private Volume Sets
>To: Multiple recipients of list HP3000-L <[log in to unmask]>
>
>     We are about to get some additional disk drives and we're
>contemplating the idea of implementing private volume sets.  I would like
to get as
>much feed back as possible about the pros and cons of doing this, as apposed to
>having them all part of the system volume set.
>
>Thanx,
>    Jon Backus
>    AB&C Group
>
>
Jon,
 
There has been lots of dialogue about the pros and cons of doing this but I
think that
we can summarize by saying the following:
 
1.  There are lots of pros.
2.  There don't seem to be any serious remaining cons.
 
The pros are:
 
1.  Better system resiliency in the event of a disk mech failure.
2.  Better overall performance due to the smoothing out of transaction
management
 posting activity (each volume set effectively receives its own XM).
3.  Better positioning for high availability solutions (mirrored disk
requires user volumes)
4.  More operational control of disk environment.  You don't need to perform
a complete
system install in order to add new disk drives.
 
The cons are:
 
1.  Initially, it's a pain in the butt to set up.
2.  Requires (slightly) more overall disk space to manage effectively.
3.  Slightly more operational awareness required in a user volume environment.
 
At HP World, several of us were involved in an HP 3000 system performance
roundtable.
I think that we reached consensus that user volumes are good but mainly for
environments
which have more than 4-5 disk drives.
 
Another issue which is of prime importance is that you must be sure to keep
enough disk
space in the MPEXL_SYSTEM_VOLUME_SET to handle all of your transient disk space
requirements.  Most of us at the conference agreed that you need a minimum
of 3-4 disk
drives to handle the transient requirements in a medium or larger installation.
 
Hope this helps.
 
Bill
---
Bill Lancaster         Lancaster Consulting
(541)926-1542 (phone)  (541)917-0807 (fax)
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