I cannot check the serverpac dialog on my 2.4 system since I've marked
the order as installed, complete, but checking what some vendors supply
for PDS's ONLY - I try not to flirt with disaster and I attempt to be
compliant as much as possible with IBM's rules, not doing so has bitten
me because I picked up an install from a previous sysprog.
with IBM ServerPac and some vendors, PDS only I am disusing these PDS's
are delivered to allow multiple extents to be taken
CHECK(IBMCSV,CSV_LNKLST_NEWEXTENTS) - tells me so
HCK detects these linklist datasets and reports on them as an ERROR
CHECK(IBMCSV,CSV_LNKLST_SPACE)
SYSPLEX: PLEX SYSTEM: SYSx
START TIME: 09/22/2022 14:01:57.366198
CHECK DATE: 20050720 CHECK SEVERITY: LOW
CSVH0979I LNKLST set LNKLST00 data sets allocated with secondary space
IBM suggests that partitioned data sets (PDS's) in the LNKLST be
allocated with only primary extents, for two reasons. First, a PDS
allocated with only primary space defined has only one extent. This
makes it easier to stay within the 255-extent limit for an active
LNKLST concatenation without having to reallocate data sets with
fewer initial extents. Second, if a PDS will be updated while in
the LNKLST set, it can be extended if it has been allocated using
secondary space. This can cause members to be placed in extents that
did not exist when the LNKLST concatenation was activated. An
attempt to access a member in a new extent causes the requesting
program to abend.
that's why I alter the allocation at ServerPac customization and not
wait till an issue arises
Carmen
On 9/22/2022 3:13 PM, Mark Zelden wrote:
On Thu, 22 Sep 2022 13:49:50 -0500, Carmen Vitullo<[email protected]> wrote:
I've been doing this on my ServerPac for a while, I've even called out
the ServerPac folks about the issue of, why deliver linklist lpalist
datasets with secondary allocation if the linkist does not support it,
Secondary extents are certainly supported in the LNKLST. What you can't do is
take a secondary to the "live" LNKLST for a PDS, but you can for PDSE and
pick up the change with an LLA REFRESH or UPDATE. For LPA libs it doesn't
matter ever since that is only read in at IPL time.
The number of extents in the LNKLST used to be a problem for some systems, but
when
the rules changed in DFSMS/MVS 1.3 to be "255 total extents or less" with PDSE
always
counting as 1 extent, that helped a lot. I personally want secondary extents,
at
least for some data sets to support applying maintenance. I always run SMP/E
apply
with COMPRESS(ALL) anyway so it's not going to continually increase and I'd
rather
get a secondary on a few libraries than have the apply blow up, have allocate a
new
larger DSN, copy old to new, rename and restart my apply. I'm pretty sure this
is
why ServerPac allocations came with secondary extents going back in history.
Due to 3390-9s geometry being my main sysres volume still, over allocation
from ServerPac (or now z/OSMF) has been more of a problem for me than
under allocation, so when building my local maintenance sysres after install I
have
had to free space on some larger PDS or PDSE files to get everything to fit and
have spare space on the sysres for maintenance. Then if something takes a
secondary during apply, I don't care. The prod LNKLSTs have secondaries on
some data sets on the sysres, but again I don't care. No one better be updating
the live sysres anyway except under extreme circumstances.
As usual YMMV and if you are in a shop with 220 LNKLST data sets you probably
have a very good reason for never wanting any secondary extents even in your
maintenance environment.
Best Regards,
Mark
--
Mark Zelden - Zelden Consulting Services - z/OS, OS/390 and MVS
ITIL v3 Foundation Certified
mailto:[email protected]
Mark's MVS Utilities:http://www.mzelden.com/mvsutil.html
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