Two years back we had an issue where the throughput of a database utility
dropped considerably (job had to be cancelled because it was too slow)
because it decided to not use more memory to do it's processing. This was
found to be because the page datasets were more than 50% utilized. The
notes
On 02/13/12 20:03, Jim Mulder wrote:
snip
Just to follow up on this, APAR OA38742 has been
opened. This problem was introduced in z/OS 1.13.
Jim Mulder z/OS System Test IBM Corp. Poughkeepsie, NY
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For IBM-MAIN
Just to follow up on this, APAR OA38742 has been
opened. This problem was introduced in z/OS 1.13.
I tried to look at the apar in IBMLINK and received this error;
An error has occurred:
* An error occurred accessing the database: RPA0 401.
Is it a security/integrity apar?
I get the
I get the same error on OA38542 and OA37992, so I think it's just SIS itself. I
opened a problem.
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No problem with me (in Belgium).
*OA38742: DIFFERENCE in ASMIORQR / ASMIORQC COUNTS become LARGE ENOUGH to
AFFECT FRAME STEAL PROCESSING and ASMIORQR INCREMENTED TOO HIGH*
During AUX paging, I/O is scheduled to drive input and/or
output I/O to auxiliary page packs. When an I/O
SIS seems to be working again.
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IBM Mainframe Discussion List IBM-MAIN@bama.ua.edu wrote on 02/03/2012
12:19:04 PM:
BTW if you have not already seen it, please look at our PMR
81276.227.000
for an agonizing saga of RSM/ASM misadventures.
JO.Skip Robinson
SCE Infrastructure Technology Services
Just to follow up on
Hi Martin,
Thanks for paging me. It is good to hear from you, and I hope that all
is well!
CPExpert has 16 checks (I call them rules) related to potential
performance problems with the paging subsystem. Included are checks
whether allocation percent exceeded guidance, checks for whether
:
Barbara Nitz nitz-...@gmx.net
To:
IBM-MAIN@bama.ua.edu,
Date:
04/02/2012 16:35
Subject:
Re: Very Lage Page Datasets (was ASM and HiperPAV)
Sent by:
IBM Mainframe Discussion List IBM-MAIN@bama.ua.edu
Charles,
I believe you're referring to the ASM_LOCAL_SLOT_USAGE
Charles,
I believe you're referring to the ASM_LOCAL_SLOT_USAGE check.
Yes, I do.
If so, this check runs at a 30 minute interval and checks the slot usage for
each in-use local paging data set regardless of whether it was defined
'statically' or added via PAGE ADD. So... it does eventually
-Manager
626-302-7535 Office
323-715-0595 Mobile
jo.skip.robin...@sce.com
From: Mark Zelden m...@mzelden.com
To: IBM-MAIN@bama.ua.edu
Date: 02/02/2012 07:35 PM
Subject:Re: Very Lage Page Datasets (was ASM and HiperPAV)
Sent by:IBM Mainframe Discussion List IBM
Are you sure that this occurs at 50% Aux. storage utilization? IRA201E
defines 'Critical storage shortage' at 85%.
See cd command, parm AUXMGMT:
SDUMP,AUXMGMT=ON or OFF
Specifies when SDUMP data captures should stop.
ON: No new dumps are allowed when auxiliary storage usage reaches 50%. New
Datasets (was ASM and HiperPAV)
Another element of paging that has not been referenced is the ability
to handle all of the swap set size in parallel. If the swap set size
is 120 pages then the old practice was to have at least four LOCALS so
each
thirty
page block of pages could be swapped
At around 50%, SVC dump will fail with 'ASM shortage'.
I think at some point, maybe 1.13, AUXMGMT=YES became the default which
prevented taking dumps at a lower aux storage percentage. You can return to the
previous default threshold by issuing this command:
CD SET,SDUMP,AUXMGMT=OFF
Barbara,
In regards to:
'I like the ASM health check that tells us that usage is 30% or more. (In
fact, I send an automated exception email every time this happens.) I hate
that ASM does not recognize that a new page data set was added. That health
check stupidly doesn't recognize a
On Thu, 2 Feb 2012 20:31:12 -0800, Skip Robinson jo.skip.robin...@sce.com
wrote:
According to conversations at SHARE, the threshold for this condition is
too conservative. AFAIK there is no APAR open to fix it. It's especially
frustrating if you want to take a dump to find out who's using up
On Thu, 2 Feb 2012 23:37:06 -0600, Barbara Nitz nitz-...@gmx.net wrote:
Mark, this came into z/OS with either 1.11 or 1.12. Some of my pagedels were an
attempt to test this behaviour. I could not test it.
I saw it on this list of changed messages on z/OS 1.11.
Skip, try ipcs active, and
Barbara wrote: Skip, try ipcs active, and then the undocumented command (IP)
ILRSLOTC. This used to be in the hidden IPCS panel that I have forgotten how to
get at
2.6i is the hidden IPCS panel.
MA
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For IBM-MAIN subscribe
: Charles Mari cm...@us.ibm.com
To: IBM-MAIN@bama.ua.edu
Date: 02/03/2012 05:46 AM
Subject:Re: Very Lage Page Datasets (was ASM and HiperPAV)
Sent by:IBM Mainframe Discussion List IBM-MAIN@bama.ua.edu
Barbara,
In regards to:
'I like the ASM health check that tells us that usage
I think the health check's way of working, to check each page dataset
for its 30%, in stead of the entire page dataset configuration, is not
such a bad one. AFAIK and some earlier posts in this thread suggested it
too: ASM has one or more groups of page datasets, depending on
devicetype, channel
On Wed, 1 Feb 2012 23:12:48 -0600, Barbara Nitz nitz-...@gmx.net wrote:
So if I have 5 3390-27 locals and they are all equally used at 50%, the
algorithms (CPU usage, not I/O) are going to pick one of them, then do the
page outs. That paging will find contiguous slots and should be efficient.
Another element of paging that has not been referenced is the ability to
handle all of the swap set size in parallel. If the swap set size is 120
pages then the old practice was to have at least four LOCALS so each
thirty
page block of pages could be swapped-in in parallel. While swapping,
I wonder what if any studies on this have been done in the lab.
It would be nice if an IBM performance expert like Kathy Walsh
could weigh in.
The last performance studies I remember for paging were
around the time of MVS XA/SP2.2.0. Very little has been done
in the area of paging
Jim Mulder d10j...@us.ibm.com wrote in message
news:of15dad2d4.112617be-on85257998.0064c1d8-85257998.0066c...@us.ibm.c
om...
I wonder what if any studies on this have been done in the lab.
It would be nice if an IBM performance expert like Kathy Walsh
could weigh in.
The last
On Thu, 2 Feb 2012 13:42:45 -0500, Jim Mulder d10j...@us.ibm.com wrote:
I wonder what if any studies on this have been done in the lab.
It would be nice if an IBM performance expert like Kathy Walsh
could weigh in.
Thanks for jumping in Jim! I hoped you or Peter would eventually
to clear
I liked Barry's plot the curve approach to this i.e. Relating occupation
to performance.
Cheers, Martin
Martin Packer,
Mainframe Performance Consultant, zChampion
Worldwide Banking Center of Excellence, IBM
+44-7802-245-584
email: martin_pac...@uk.ibm.com
Twitter / Facebook IDs: MartinPacker
On Thu, 2 Feb 2012 21:48:17 +, Martin Packer martin_pac...@uk.ibm.com
wrote:
I liked Barry's plot the curve approach to this i.e. Relating occupation
to performance.
What is the SSCH count in VMAC74? SIO74CNT ?
With a static environment for the most part (except after IPL when all the
...@mzelden.com
To: IBM-MAIN@bama.ua.edu
Date: 02/02/2012 01:02 PM
Subject:Re: Very Lage Page Datasets (was ASM and HiperPAV)
Sent by:IBM Mainframe Discussion List IBM-MAIN@bama.ua.edu
On Thu, 2 Feb 2012 13:42:45 -0500, Jim Mulder d10j...@us.ibm.com wrote:
I wonder what if any studies
On Thu, 2 Feb 2012 16:50:44 -0800, Skip Robinson jo.skip.robin...@sce.com
wrote:
There is a much lower limit to worry about than the one that prevents new
works from starting. At around 50%, SVC dump will fail with 'ASM
shortage'. This barrier has been discussed recently at SHARE. IBM agrees
SHARE MVS Program Co-Manager
626-302-7535 Office
323-715-0595 Mobile
jo.skip.robin...@sce.com
From: Mark Zelden m...@mzelden.com
To: IBM-MAIN@bama.ua.edu
Date: 02/02/2012 07:35 PM
Subject:Re: Very Lage Page Datasets (was ASM and HiperPAV)
Sent by:IBM Mainframe Discussion
If the reason field shows A CRITICAL AUXILIARY STORAGE SHORTAGE EXISTS,
first you need to ensure that enough DASD resource is available for
captured dumps to be written out. Then, consider adding additional
auxiliary storage (paging) resources, because SVC dumps will not be
allowed again until the
Infrastructure Technology Services
Electric Dragon Team Paddler
SHARE MVS Program Co-Manager
626-302-7535 Office
323-715-0595 Mobile
jo.skip.robin...@sce.com
From: Barbara Nitz nitz-...@gmx.net
To: IBM-MAIN@bama.ua.edu
Date: 02/02/2012 09:47 PM
Subject:Re: Very Lage Page Datasets (was ASM
Wow. Very interesting. PFA was just complaining about super hog address
space DA20DBM1. Here's what ILRSLOTC shows as the top piggy:
VERSION 02/18/2010
ASID=0079 JOB=DA20DBM1 SLOTCOUNT=00029E21 VIO COUNT=
I love it when a picture comes together.
Yeah, and the DB admins will tell you
How about a new keyword DUMP=dsn,dsn similar to LOCAL=dsn,dsn for a
Local paging dsn used only for dumps?
On Thu, Feb 2, 2012 at 10:31 PM, Skip Robinson jo.skip.robin...@sce.com wrote:
IEE711I SYSTEM DUMP NOT TAKEN. A CRITICAL AUXILIARY STORAGE SHORTAGE
EXISTS
From the message manual:
If
On Tue, 31 Jan 2012 22:49:53 -0600, Barbara Nitz nitz-...@gmx.net wrote:
Writing to contiguous slots and over allocation is mentioned, but unless I
missed it the old ROT (and health check) of not having more than 30%
of the slots allocated is not specifically addressed. Certainly with 4K
pages
...@uk.ibm.com
Twitter / Facebook IDs: MartinPacker
Blog:
https://www.ibm.com/developerworks/mydeveloperworks/blogs/MartinPacker
* Kathy's the real expert to defer to
From:
Mark Zelden m...@mzelden.com
To:
IBM-MAIN@bama.ua.edu,
Date:
01/02/2012 15:48
Subject:
Re: Very Lage Page Datasets (was ASM
List [mailto:IBM-MAIN@bama.ua.edu] On Behalf
Of Barbara Nitz
Sent: Tuesday, January 31, 2012 10:50 PM
To: IBM-MAIN@bama.ua.edu
Subject: Re: Very Lage Page Datasets (was ASM and HiperPAV)
Writing to contiguous slots and over allocation is mentioned, but
unless I missed it the old ROT (and health check
So if I have 5 3390-27 locals and they are all equally used at 50%, the
algorithms (CPU usage, not I/O) are going to pick one of them, then do the
page outs. That paging will find contiguous slots and should be efficient.
BTW, this is just an example, we still try to keep our 3390-27 local usage
: Wednesday, February 01, 2012 9:13 PM
To: IBM-MAIN@bama.ua.edu
Subject: Re: [IBM-MAIN] Very Lage Page Datasets (was ASM and HiperPAV)
So if I have 5 3390-27 locals and they are all equally used at 50%, the
algorithms (CPU usage, not I/O) are going to pick one of them, then do
the page outs
On Mon, 30 Jan 2012 22:35:02 +, Martin Packer martin_pac...@uk.ibm.com
wrote:
Because
of the virtualisation within modern disk controllers robustness favours
more, smaller.
What 6-9 3390-27 page volumes isn't robust enough? :-)
And regardless of PAV and where the physical location is on
Mark Zelden m...@mzelden.com wrote in message
news:9474272146773836.wa.markmzelden@bama.ua.edu...
On Mon, 30 Jan 2012 22:35:02 +, Martin Packer
martin_pac...@uk.ibm.com wrote:
Because
of the virtualisation within modern disk controllers robustness
favours
more, smaller.
What
On Tue, 31 Jan 2012 08:48:30 -0600, Mark Zelden m...@mzelden.com wrote:
On Mon, 30 Jan 2012 22:35:02 +, Martin Packer martin_pac...@uk.ibm.com
wrote:
Because
of the virtualisation within modern disk controllers robustness favours
more, smaller.
What 6-9 3390-27 page volumes isn't robust
In 7649945814757037.wa.nitzibmgmx@bama.ua.edu, on 01/30/2012
at 11:41 PM, Barbara Nitz nitz-...@gmx.net said:
(Due to a clear abend0c4-4 on two getmained addresses in a BMC
utility that they say is caused by not-enough-storage above the bar.)
Tell them to look again. It may be more likely
Barbara, yes you will. :-) Sounds like your DB2 folks are trying to write
GENEROUS cheques and make YOU cash them, memorywise :-) Let me at'em. :-)
(I happen to be in SVL at DB2 Boot Camp where John Campbell presented on
this yesterday - corroborating my viewpoint.)
Cheers, Martin
Martin
On 1/31/2012 7:07 AM, Vernooij, CP - SPLXM wrote:
About health checks: I consider at least 50% of them being writen on a
lost Friday afternoon, because of some target to just deliver health
checks.
Sometimes the need for the appearance of an autonomic, self-healing system
becomes more
Writing to contiguous slots and over allocation is mentioned, but unless I
missed it the old ROT (and health check) of not having more than 30%
of the slots allocated is not specifically addressed. Certainly with 4K
pages (for the most part) and 3390-27 (or bigger) that 30% ROT doesn't
apply
Barbara Nitz nitz-...@gmx.net wrote in message
news:0492432665216573.wa.nitzibmgmx@bama.ua.edu...
See APAR OA32453 (closed last year). It addresses the problem(s)
associated with using HYPERPAV (and the WLMPAV option) for paging
devices.
If I read the apar right, this addresses the WLMPAV
To be precise: ASM reserves 2 exposures *per pagedataset* not per
volume (i.e. 2n-1 Aliasses per volume), since/so you can allocate more
than 1 pagedataset on one volume. We do so to fill 3390-9s and -27s with
pagedatasets.
I beg to disagree. :-) HiperPAV works on a per-IO-basis in the hardware,
paging requests filled.
Barbara
Diagrement permitted.
I was referring to the pre-hiperpav ASM algorithmes, where it ensured
that PAVS guaranteed 2 I/Os to each pagedataset.
Kees.
For information, services and offers, please visit our
On Mon, 30 Jan 2012 11:39:20 +0100, Vernooij, CP - SPLXM
kees.verno...@klm.com wrote:
To be precise: ASM reserves 2 exposures *per pagedataset* not per
volume (i.e. 2n-1 Aliasses per volume), since/so you can allocate more
than 1 pagedataset on one volume. We do so to fill 3390-9s and -27s
.com
1830 East Paris, Grand Rapids, MI 49546 MD RSCB2H
p 616.653.8429
f 616.653.2717
-Original Message-
From: IBM Mainframe Discussion List [mailto:IBM-MAIN@bama.ua.edu] On
Behalf Of Mark Zelden
Sent: Monday, January 30, 2012 10:34 AM
To: IBM-MAIN@bama.ua.edu
Subject: Re: ASM and HiperPAV
See my reply to Mark for the non-Hiperpav environment.
What does ASM do in Hiperpav environment? I cannot make this up from the
APAR Barbara mentioned.
Kees.
Jousma, David david.jou...@53.com wrote in message
news:a90766b5039c59409110c92d47216f590677b...@s1flokydce2k322.dm0001.in
fo53.com
Mark Zelden m...@mzelden.com wrote in message
news:1732118085814428.wa.markmzelden@bama.ua.edu...
On Mon, 30 Jan 2012 11:39:20 +0100, Vernooij, CP - SPLXM
kees.verno...@klm.com wrote:
To be precise: ASM reserves 2 exposures *per pagedataset* not per
volume (i.e. 2n-1 Aliasses per
On 01/30/12 10:33, Mark Zelden wrote:
snip
You've been able to allocate a page ds larger than 4G for quite some time
now (since z/OS 1.8 + OA20749). On our largest systems, we allocate a
single local page dataset per 3390-27 volume.
In one of the environments I support I couldn't turn on
616.653.2717
-Original Message-
From: IBM Mainframe Discussion List [mailto:IBM-MAIN@bama.ua.edu] On
Behalf Of Mark Jacobs
Sent: Monday, January 30, 2012 10:57 AM
To: IBM-MAIN@bama.ua.edu
Subject: Re: ASM and HiperPAV
On 01/30/12 10:33, Mark Zelden wrote:
snip
You've been able
49546 MD RSCB2H
p 616.653.8429
f 616.653.2717
-Original Message-
From: IBM Mainframe Discussion List [mailto:IBM-MAIN@bama.ua.edu] On
Behalf Of Jousma, David
Sent: Monday, January 30, 2012 11:11 AM
To: IBM-MAIN@bama.ua.edu
Subject: Re: ASM and HiperPAV
Mark,
See OA20749
The MVS
On Mon, 30 Jan 2012 10:57:25 -0500, Mark Jacobs mark.jac...@custserv.com
wrote:
On 01/30/12 10:33, Mark Zelden wrote:
snip
You've been able to allocate a page ds larger than 4G for quite some time
now (since z/OS 1.8 + OA20749). On our largest systems, we allocate a
single local page
On Mon, 30 Jan 2012 10:52:18 -0500, Jousma, David david.jou...@53.com wrote:
So what is the current thinking on the ROT for page space? Is one 27GB
page dataset better than 2 13Gb page datasets on the same volume? Is it
a wash?
More is better. You should have at least 3 locals and that was
On Mon, 30 Jan 2012 17:00:04 +0100, Vernooij, CP - SPLXM
kees.verno...@klm.com wrote:
See my reply to Mark for the non-Hiperpav environment.
What does ASM do in Hiperpav environment? I cannot make this up from the
APAR Barbara mentioned.
I don't know what is being done exactly either, but I
-MAIN@bama.ua.edu
Subject: Re: ASM and HiperPAV
Mark,
See OA20749
The MVS Initialization and Tuning Guide (SA22-71591-04) in
section 2.2 Page Data Set Sizes indicates page datasets can be
no more than 1M (1,048,576) slots (4GB) in size. As of z/OS
R1.8, this is no longer true, page
On 01/30/12 11:21, Mark Zelden wrote:
snip
Yes, you are. z/OS 1.8 added the support but ASM forgot to. :-) . That APAR
FIXED the problem so ASM did support it. That was why I said you
needed z/OS 1.8 PLUS the fix for APAR OA20749.
Regards,
Mark
--
Mark Zelden - Zelden Consulting
in the past) then HiperPAV is effectively not used.
Other than for the second case that Jim Mulder had detailed in the
past. Hence my question if that is still true or if ASM now starts
as many IOs as needed to get paging requests filled.
For a page data set on a HiperPAV device, ASM creates two
IBM Mainframe Discussion List IBM-MAIN@bama.ua.edu wrote on 30/01/2012
22:10:39:
From:
Jim Mulder d10j...@us.ibm.com
To:
IBM-MAIN@bama.ua.edu,
Date:
30/01/2012 22:14
Subject:
Re: ASM and HiperPAV
Sent by:
IBM Mainframe Discussion List IBM-MAIN@bama.ua.edu
For a page data set on a HiperPAV device, ASM creates two
sets of channel program control blocks. If a single page read
request come along while the first set is in use, ASM will use
the second set to start another channel program to do the single
page read. The purpose is to avoid having
See APAR OA32453 (closed last year). It addresses the problem(s) associated
with using HYPERPAV (and the WLMPAV option) for paging devices.
If I read the apar right, this addresses the WLMPAV option in that it is no
longer needed to be set. How many IOs does ASM start concurrently to the same
Barbara,
See APAR OA32453 (closed last year). It addresses the problem(s) associated
with using HYPERPAV (and the WLMPAV option) for paging devices.
Regards,
Charles Mari
IBM - ASM/RSM Development
What is the current wisdom on ASMs usage of HIPERPAV? Is ASM still only using
two IOs per page data set or has that been fixed? The last definitive word I
found about this was by Jim Mulder at the end of 2009 (not fixed).
Thanks, Barbara
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