Unless something has changed since I last inspected it CA's VM:Secure and VM:Direct "COMPRESS" subcommand, it compresses space within specified subpools (a good thing) within single DASD volumes. Sadly, it still does not perform cross-volume compression -- something we've always wanted, and what REALLY provides good chunks of free space.
But it is possible using REXX, CMS Pipelines, and VM:Secure or VM:Direct commands, to write your own cross-volume subpool compression command. We did, and run it each night, but it is not clean enough to be made available. I'd be happy to share it with C.A. if they are interested.
The basis strategy was to find the biggest free-space in the specified subpool, on any DASD in the subpool, and keep moving MDISKs AWAY from the edge of that free-space. When examining the adjoining MDISKs, the larger of the two was moved first. Starting with the biggest free space reduces the number of MDISKs needing to be moved, and gives you a consistent strategy to follow.
Mike Walter
Hewitt Associates
The opinions expressed herein are my own, not those of my employer.
| "Imler, Steven J"
<[EMAIL PROTECTED]>
Sent by: "VM/ESA and z/VM Discussions" <[email protected]> 12/24/2005 10:01 AM
|
|
CA's VM:Secure/VM:Direct has a "DASD defrag" (compress) function ...
JR Imler
JR (Steven) Imler
Computer Associates
Senior Software Engineer
Work: +1 703 708 3479
Fax: +1 703 708 3267
[EMAIL PROTECTED]
[EMAIL PROTECTED]
-----Original Message-----
From: VM/ESA and z/VM Discussions [mailto:[EMAIL PROTECTED] On
Behalf Of Jim Bohnsack
Sent: Friday, December 23, 2005 02:06 PM
To: [email protected]
Subject: Re: Minidisk defragger?
DFSMS will work, even without ISPF, altho not as easily. Maybe Kris
Buehlen's DRM would fill that gap. I haven't tried it tho.
Jim
At 02:29 PM 12/22/2005, you wrote:
>Adam Thornton wrote:
>
>>I find, after using DIRMAINT for a long time, that I actually have
>>quite a lot of free DASD, but it's carved up into little islands
>>scattered around my volumes. If I could consolidate those gaps into
>>fewer, larger gaps, I'd be in much better space for allocating disks
>>for Linux guests.
>>
>>Is there a zero-cost tool that will do this defragmentation for me?
>
>
>A long time ago, at a university far, far away, I used to use DFSMS's
ISPF
>interface for that task. It might worth looking to see if there's a
>line-mode command for DFSMS that would do the same thing. DFSMS is free
>now, although ISPF, of course, isn't, hence the thought about line-mode
>commands for that function.
Jim Bohnsack
Cornell Univ.
(607) 255-1760
The information contained in this e-mail and any accompanying documents may contain information that is confidential or otherwise protected from disclosure. If you are not the intended recipient of this message, or if this message has been addressed to you in error, please immediately alert the sender by reply e-mail and then delete this message, including any attachments. Any dissemination, distribution or other use of the contents of this message by anyone other than the intended recipient is strictly prohibited.
