Frank,

You have lots of good feedback as far as sharing with integrity and security
go, but I did focus on comment below about performance impact. There is
always the likelihood that activity from one LPAR may impact the performance
of another, and it can happen for the SYSRES volumes just as easily as any
other volumes.

The thing is that the chance of this impact is quite small, and can be kept
that way by proper measurement and tuning, which is something that is also
missing in the Open Systems arena. I've seen poor LLA parms on a Dev system
start to cause this sort of contention on SYSRES, but a review of LLA and
VLF fixed this and improved performance for both Dev and Prod.

Duplicating volumes just in case you have a performance problem is liking
pulling out your teeth in case you get a hole in them. If the combined
activity from each LPAR is already low then it is a no brainer.

If the CIO requires separation for performance reasons, then where do you
stop? Should there be separate channels and switches? Should DEV and Prod
have dedicated Parity Groups? Should Dev and Prod have their own cache
partitions? Etc. Where would it stop?

Ron

> 
> Now the discussion has "blown up" in that there are now questions by our
CIO
> as to if we really should be sharing even the "executable" libraries.  Not
> only at the applications level, but also at the systems level.  He's
thought
> is that if two LPARs share the same OS executables that their use in DEV
could
> possibly hinder performance of PROD.
> 

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