On Sun, 12 Feb 2006 19:27:28 -0600, Alan Ackerman 
<[EMAIL PROTECTED]> wrote:

>The big advantage of VM nowadays is the sharing of real memory. LPARs ca
n 
share processor and 
>channels and devices. Minidisks are pretty small, for z/OS there is 
usually no particular advantage 
>to them.

The Minidisk advantage I was thinking about for this environment is mostl
y 
because of the DASD being on an ESS 800.  Unlike a DS6800, the ESS 800 

can't delete individual volumes to free the space for making new volumes 

of different sizes.  On the ESS 800 you have to delete every volume in th
e 
LCU.  I was thinking how much more flexiblity it would add to the DASD 

management on z/OS if Minidisks were used to make some smaller volumes ou
t 
of larger ones when needed and stick to dedicated volumes otherwise (for 

PAV reasons).

>Generally, each group (for example the IMS group, the DB2 group, the z/O
S 
group, etc.) has its 
>own set of z/OS test guests. This has the big advantage that when the 

phone rings and the system 
>programmer has to "leave" to fix a production problem, he (or she) 
doesn't lose his (or her) test 
>shot -- when they come back, the guest is waiting where they left off. 

Most of the pages are 
>paged out, so they don't cost much. (Even an "idle" z/OS guest  consumes
 
cycles, alas.) 

That's one of the big benfits I'd included under "new guests on demand". 
 
Right now they singly resuse a test LPAR.  Under VM they can have more.

Brian Nielsen

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