----- Original Message -----
From: ""Ted MacNEIL"" <[EMAIL PROTECTED]>
Newsgroups: bit.listserv.ibm-main
Sent: Wednesday, April 25, 2007 12:45 PM
Subject: Re: Do we have to defrag MVS volumes on newer generation disk
arrays?
>My guess is that we do, because it still looks like (E)CKD to z/OS.
Yes. You have to.
We have a DS8300, and we are still running DEFRAG.
The problem is due to the same ECKD limitations being carried forward.
Doesn't really have anything to do with ECKD, it has more to do with how
DADSM allocates datasets on a volume. He still looks at the freespace in
the VTOC, so if the freespace ain't contiguous, some allocations may still
fail. Most DEFRAGs will use FlashCopy or SnapShot under the covers, so you
shouldn't see the huge times in ENQ and data movement that you used to see
with DEFRAG (or COMPAKTOR if using FDR).
Regards,
Tom Conley
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