All,

Shmuel's reply prompts me to suggest that you consider what lies outside the 
nine dots.

Firstly, would you consider thin provisioning of the installation volumes and 
SYSRES? This will get you onto 3390-A for these volumes using any size you 
want. Why is this good? Because DVE is also good. If you start out with 32K 
Cyls and later find it is not enough, just make the volume bigger. You need 40K 
Cyls, then just add 8K Cyls to the existing volumes. Sounds easy, but I'm not a 
software jockey.

Second thing is ignore the previous paragraph and just allocate full sized 
3390-A volumes with 262K Cyls. If you don't use the space on the volume then 
you don't use space in the disk array, and I think it will be some time before 
Serverpac manages to fill one of these pupies. All those that worked with RVA 
will remember over provisioning with 3390-3 when you only needed 3390-1 for 
your JES2 Checkpoint.  This is the same thing.

Finally,  make all the data sets ten (yes 10) times larger than they need to 
be, with ten times the directory blocks you think you want. It is the same 
principle as above: if you don't use the space on the volume then you don't use 
the space in the disk array,

OK, there is a sanity check on the the space you use in the array because of 
the page allocation boundaries. IBM uses 1GB pages, HDS uses 32MB pages, and I 
think EMC use 14MB pages. So an empty volume with just a VTOC & VVDS will 
consume 1GB, 32MB, and 14MB respectively from the pool of each vendor. For EMC 
and HDS the fragmentation generated by the Cylinder allocation area with just a 
VTOC , and the empty space in datasets is fairly small and does not 
dramatically inflat the pool usage (remember NCL?), but for IBM the 1GB page 
size may need some monitoring.

Embrace the future of z, because it is already here. Now you guys that know 
better can shoot me down: shields are up :-)

Ron






Sent via the Samsung Galaxy Note® 8.0, an AT&T 4G LTE tablet

-------- Original message --------
From: "Shmuel Metz (Seymour J.)" <[email protected]> 
Date: 04/30/2014  15:01  (GMT-08:00) 
To: [email protected] 
Subject: Re: [IBM-MAIN] New install library size 
 
In <[email protected]>, on 04/30/2014
   at 01:55 PM, John Eells <[email protected]> said:

>As some have observed, not everything can be a PDSE. 

Then I urge you to overallocate directory entries.

-- 
     Shmuel (Seymour J.) Metz, SysProg and JOAT
     ISO position; see <http://patriot.net/~shmuel/resume/brief.html> 
We don't care. We don't have to care, we're Congress.
(S877: The Shut up and Eat Your spam act of 2003)

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