On 01/21/2012 04:21 PM, retired mainframer wrote:
:>:-----Original Message-----
:>:From: IBM Mainframe Discussion List [mailto:[email protected]] On
:>:Behalf Of Joel C. Ewing
:>:Sent: Saturday, January 21, 2012 8:02 AM
:>:To: [email protected]
:>:Subject: Re: PDSE
:>:
:>:So the only functionally-equivalent, officially-sanctioned way to
:>:accomplish this goal is still to
:>:(1) create a new dataset with a different name and copy the data to it,
:>:(2) modify PARMLIB LNKLST defs to replace the old library in linklist
:>:with the new at next IPL,
:>:(3) IPL.
:>:And if for some reason you really must have the original dataset name,
:>:repeat the process to get back to the old name.
If you need the original DSN, after populating the new dataset, uncatalog
the original and rename the replacement (both actions not restricted by the
current enqueue). This will eliminate the need for the second IPL. And
after the IPL, you can rename the original dataset and delete it even though
the DSN is enqueued by LLA (assuming you the correct RACF access).
This technique is only possible if it is acceptable for the replacement
DSN to be on a different volume, AND the original DSN volume is not an
SMS volume, but I too have used this in the past when system datasets
were divided between two non-SMS volumes and volume residency didn't
matter.
One must also recognize that there is a slight risk here: that between
the "uncatalog" step and the final "rename" there is a window during
which the system is in a state where a successful IPL may not be
possible should the system crash; so to not tempt fate, you don't want
to do this during a storm when the UPS is down or elongate the window by
allowing yourself to be interrupted in the middle of the process -- and
having an alternative recovery system available for the unlikely
worst-case scenario is goodness. I was never hit by a system failure in
the middle of one of these sequences, but I am convinced it is only
because I was sufficiently paranoid and Murphy knew I had recovery
alternatives at hand.:)
If the object is to find, if possible, a procedure which passes through
no window of risk where a system outage could leave you unable to IPL,
then to preserve the original DS name I think you are stuck with two
IPL's -- an unpleasant enough prospect that most SysProgs quickly learn
alternatives (like the one above) that accept some tolerable level of risk.
--
Joel C. Ewing, Bentonville, AR [email protected]
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