My context was backup/recovery. Page datasets tend to be large and so numerous
as to fully occupy whole volumes in the first place. DASD is too cheap to fret
about a couple of cylinders here and there.
With two exceptions, backing up page volume makes no sense to me. One exception
is that it is much simpler to restore a page volume than to allocate the page
datasets by hand. The other exception is having data on these volumes.
Once had an LPAR load a wait PSW once when a volume backup job on another LPAR
sat on a page volume a bit too long. Most would call that a performance hit.
Don't recall, but that may have been before PAV.
So, the simple way out is ban data (dedicate the volume) and exclude page
volumes from routine backups and mirroring. We don’t fool with page or JES
volumes.
Being a simple minded sort, simple solutions have some appeal to me. ;-)
-----Original Message-----
From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On Behalf Of Ron
Hawkins
Sent: Wednesday, May 07, 2008 11:41 AM
To: [email protected]
Subject: Re: PPRC and page datasets
Hal,
I don't think that is true anymore. The reason for dedicating page datasets to
a single volume was to stop the "seldom ending" channel programs from ending.
I'm sure I read on this list that the suspend/resume subchannel commands are
not used by ASM anymore, so there is no reason to dedicate.
And if this is not the case, have you been paging heavily enough that seldom
ending channel programs will make a huge difference to a Demand page-in?
There is also PAV exploitation for page datasets to consider.
Ron
> -----Original Message-----
> From: IBM Mainframe Discussion List [mailto:[EMAIL PROTECTED] On
> Behalf Of Hal Merritt
> Sent: Wednesday, May 07, 2008 8:02 AM
> To: [email protected]
> Subject: Re: [IBM-MAIN] PPRC and page datasets
>
> General case is a performance hit that does not add value. Volumes with
> page datasets shouldn't have anything else.
>
> My $0.02
>
NOTICE: This electronic mail message and any files transmitted with it are
intended
exclusively for the individual or entity to which it is addressed. The message,
together with any attachment, may contain confidential and/or privileged
information.
Any unauthorized review, use, printing, saving, copying, disclosure or
distribution
is strictly prohibited. If you have received this message in error, please
immediately advise the sender by reply email and delete all copies.
----------------------------------------------------------------------
For IBM-MAIN subscribe / signoff / archive access instructions,
send email to [EMAIL PROTECTED] with the message: GET IBM-MAIN INFO
Search the archives at http://bama.ua.edu/archives/ibm-main.html
