Mainframe, Performance, Topics Podcast

By Marna WalleTechnology

Mainframe, Performance, Topics Podcast episodes

September 02Episode 37 "Watts Up"
Episode 36 "Watts Up"
What’s New
z17 ME2, single frame and rack mount!
Webpage of the Moment: Java dependencies for z/OS elements and components We've moved z/OS dependency from Semeru 21 to 25!
Mainframe - New System Recovery Boost Goodies
Provided in OA66837
Message enhancement, more information in SMF 90.40 and 89.
New Recovery Process Boost for dynamic I/O activation. There are now 8 of these types of recovery process boosts.
Available on z/OS 3.1 and higher, for z16 and higher.
Performance - IBM z17 Sustainability Metrics
Power consumption data is provided on z/OS 3.1 and higher, in SMF 70.1 CPU Control Section.
Available at both LPAR and Machine level.
Machine consumption level has: infrastructure, unassigned (not deployed to any LPAR), and total.
LPAR consumption level has: CPU (both GCP and zIIP), memory, and I/O.
Martin's observations: LPAR consumption is largely driven by CPU, and there is a substantial amount of non-LPAR power consumption.
Topics - Restarting Things
Martin and Marna discuss why software gets restarted (z/OS IPLs and middleware restarts).
Martin has noticed in engagements that it takes time for things to warm up. Most notably, Db2 buffer pools maturing.
It is helpful to know when your warm-up period happens, such that you can be ready when your heaviest workload arrives.
Restarts don't necessarily mean a workload or service outage, because of IBM Z technology advances (sysplex, workload balancing, ...)
On the blog
⁠Marna's blog⁠
⁠Martin's blog
So It Goes⁠
48 min
April 08, 2025Episode 36 "Telum Like It Is"
Episode 36 "Telum Like It Is"What’s New
z/OS dependencies moved from Semeru 17 to 21. EOS for Semeru 11 is 30 Nov 2025.
Manual of the Moment: z/OS 3.1 Planning for Installation refresh, Software Dependencies section
Mainframe - Position z/OS for IBM z17
z/OS V2.4 and higher is supported on IBM z17. Use SMP/E FIXCATs to find the necessary service.
z/OS Sysplex requirements for coexistence is z15, z16, and z17.
Exploitation for z17 in z/OS includes: Workload level sustainability and power consumption, Workfload classification pricing, new CL6 link technology, BCPii and HMC hardened security, CF Level 26, and more.
Mainframe Also - Preview of z/OS 3.2
z/OS 3.2 will IPL on z15 and higher servers. Planned GA is 3Q2025.
Some new functions previewed, but stay tuned for further announcements with more complete functions.
Highlights: new REST APIs for doing installation of service updates, support for direct encryption to tape, new z/OSMF Storage Management interface, RACF certificate support for multiple altnames, and more.
Performance - IBM z17 highlights
Telum 2 processor has the 2nd generation on-chip AI accelerator, with 8-bit integer (INT8) and 16-bit floating point (FP16) datatypes for more thruput.
5nm (from 7nm), with clock speeed of 5.5 GHz (from 5.2).
DPU has 4 port cards (from 2), with energy consumption reduction. DPU accessible from other chips and DCMs.
1 to 4 processor drawers. 4-drawer models are Max183 and Max 208.
Memory 64 TB (from 40).
Measurements with new Channel Measurement Groups 4 and 5, with SMF 73 support.
Topics
Martin and Marna discuss how they prepared materials for IBM z17, with the Upgrade Workflow and Redbooks.
On the blog
Marna's blog
Martin's blogsSo It Goes
39 min
October 28, 2024Episode 35 "In search of EXCELence?"
What’s New
z/OS dependencies moved from Semeru 11 to 17 before November 2025

Manual of the Moment: MVS Extended Addressability Guide for learning about address spaces, data spaces, and hiperspaces.
Mainframe - Looking at ages of fixes you haven't installed yet
IBM has started adding a REWORK date to PTFs. The date may be a day or two before the actual availability date.
Use case example: requirement with a policy that Security/Integrity (SECINT) PTFs that meet some criteria must be installed within xx days of availability.

Fits nicely with the z/OS UUID support, from Episode 34.
Performance - Drawers, Of Course
Martin explores the IBM z16 drawers, frames, and cache hierarchy.

All of an LPAR’s logical processors and memory should be in the same drawer.

Important because cross-drawer memory and cache accesses are expensive.
Topics - Excel Love It Or Hate It
Martin and Marna discuss how they use Excel, and what they like and dislike about it.

Graphing and customization difficulties were investigated.
On the blog
Marna's blog

Martin's blogs
So It Goes...
48 min
December 06, 2023Episode 34 "Homeward Bound"
Episode 34 "Homeward Bound"
Mainframe - z/OSMF Software Management UUID
What it is: ability to programmatically retrieve a unique value (UUID) which can then be used to find out installation information about the active z/OS system. This function is optional.
Requires: z/OS 3.1, an SMP/E CSI specific to that software instance, and an installed usermod which is provided by z/OSMF Software Management.
How it works: once the UUID has been encoded into your z/OS system's LPALIB data set, you can use a REST API to retrieve the UUID. Then, this allows you to use the UUID to run many other REST APIs to look at the installed software with assurance that you are looking at the actively running system software instance. You must ensure that for each new software instance, you install a new UUID. The UUID is also available from the D IPLINFO command.
Performance - Logical Processor Home Addresses
This is the LPAR's preferred physical location for a specific logical process to be dispatched. Drawer, DCM, chip, core. Degrees of meaning for Verical High, Medium, Low, and Dedicated.
z16 support is in the SMF 70-1 records, OA62064 . Better than SMF 99-14 in some ways.
Useful for an analysis of effect of PR/SM weights and HiperDispatch, verify location of ICF and IFL LPARs.
Logical processor is not always dispatched to its home address. VH and Dedicated will always dispatch to the home processor. Location of memory is not included, although SMF 113 gives hints.
Might need SMF 99-14 in addition, as it has affinity nodes, which 70-1 doesn't.
All in all, a very useful advancement in the instrumentation.
Topics - Useful Tips for Debugging a DFSORT E15 Exit
Martin explores his experiences with DFSORT E15 and offers advice.
DFSORT E15 is great at flattening records and enhancing filtering. You might find yourself needing to maintain this exit, which others have written.
Some useful advice is: let the exits do the I/O for you, do a COPY first, stop after one record at first, write diagnostic data into output records, forcing an abend can help, code a SYSUDUMP DD, maintain a DFSORT symbols convention, GETMAIN your working storage, and you can write to the spool.
On the blog
Marna's blog
Martin's blogs
So It Goes
36 min
July 05, 2023Episode 33 "These Boots Were Made"
Episode 33 "These Boots Were Made"
What’s New
Preliminary z/OS 3.1 Upgrade materials

Python 3.1.1 zIIP enablemment OA63406 and PH52983
Mainframe -
Requires: z/OS V2.5 with PTFs, IBM z16 with microcode. Has both driving and target system requirements, use IBM.Function.ValidatedBoot FIXCAT.

Front end: Siging the in-scope artifacts (NUCLEUS, LPA, IPL Text, and SA Dump Text), z16 is not required here although z/OS V2.5 and PTFs are.

Back end: Verification of those signed in-scope artifacts. z16 with correct microcode level is required here (with z/OS V2.5 and PTFs).

Security set up work is required.
Performance - Open Data Sets, Part 2
Follow on, from Part 1 which was physical open and close of data sets as seen by z/OS.

This is about Db2 with the notion of logically Open and Closed data sets.

Its main role is to manage inter-Db2 read/write interest, for Datasharing efficiency purposes.

Two Db2 subsystem parameters have traditionally been used to control pseudoclose: PCLOSET and PCLOSEN. PCLOSEN is gone in V12 with APAR PH28280, as part of a DSNZPARM simplification effort. So PCLOSET would need adjusting down to whatever mimics PCLOSEN - in anticipation of this APAR or V13.
Topics - Messing With Digital Electronics
Martin explores his experiences with input devices (Stream Decks, Quick Keys, ...)

Martin has even built his own input devices: having an RFID card kick off automation, rotary encoders, USB Human Interface Device.
On the blog
Marna's blog

Martin's blogs
So It Goes
41 min
April 21, 2023Episode 32 "Scott Free"
Episode 32 "Scott Free"
What’s New
Preview of z/OS 3.1
Mainframe - SMFLIMxx Parmlib Member
IEFUSI exit replacement with a parmlib member, related to storage and limits that can be specified.
Functions are delivered as continuous delivery, such as the SAF check filter, and number of shared pages used.
In z/OS 3.1: Dedicated Real Memory Pools to assign memory to a specific application, like zCX, in all frame sizes.
Performance - Open Data Sets, Part 1
Looking at many open data sets (100s of thousands) for middleware.
ALLOCxx's SWBSTORAGE has to specify ATB to put control blocks above the bar. Applications need to exploit the service.
Monitoring virtual storage is key here, and remains important. The number of volumes needed affects how much memory is needed, so there is no one answer.
Topics - Evolution of a Graph
Martin explores the large improvements he's made with his custom graphing programs.
Start with naive rows and columns, with rigid labels.
Then, generating the titles with REXX. Then, using REXX to drive GDDM directly. Then, use REXX to generate many more data point and plotting them directly. Then, have REXX generate the series names.
Martin encourages all to evolve their graphs, to tell the story better, and run more efficiently.
Customer Requirement
ZOSI-2195 "Extended GDG causes space issues", has been satisfied. IGGCATxx's GDGLIMITMAX with OA62222 on V2.3.
On the blog
Marna's NEW blog location is here
Martin has quite a few new blog articles here
So It Goes
42 min
July 11, 2022Episode 31 "Take it to the Macs"
Episode 31 "Take it to the Macs" show notes.
This episode is about our After Show. (What is that?) Long show notes can be found here.
What’s New
New news for CustomPac removal date, it is July 10, 2022.

Data Set File System released OA62150 closed April 28th, 2022 only on z/OS V2.5
Mainframe - z/OS Management Services Catalogs: Importance of z/OSMF Workflows
z/OS Management Services Catalog, zMSC, allows you to customize a z/OSMF Workflow for your enterprise, and publish it in a catalog for others to "click and use".

There are 7 initial sample Services that IBM provides, or you can provide your own with a starting Workflow.

zMSC Services are based on z/OSMF Workflows. You can see why the discussion on knowing z/OSMF Workflows is important.
Performance - System Recovery Boost (SRB) Early Experiences
System Recovery Boost provides boosts of two kinds: speed and zIIP.

There are different capabilities of SRB, based on which HW server you are running (z15 or z16):Shutdown - which allows you to have 30 minutes worth of boosting during shutdown. This function must be requested to be used each time.
IPL - which allows you to have 60 minutes worth of boosting during IPL. This function, provided by default, is on.
Recovery Process Boost, provided on IBM z15. Extends to structure or connectivity recovery, for instance.
Newer additional functions for Recovery Process Boost, specifically on IBM z16, for stopping and starting certain middleware.

Martin has several early field experience, which he has summarised in four blog posts.
Topics - Stickiness
This topics explores what makes some technologies sticky, and some not.

Martin and Marna discuss some of the attributes are important for continuing to be used, and what makes a function fall away over time.Value
Completeness
Usability and immediacy
Reliability
Setup complexity
On the blog
Marna's blog is here

Martin has quite a few new blog articles here
So It Goes
45 min
March 16, 2022Episode 30 "Choices Choices"
Short show notes - long show notes here
We have a special guest joining us for the performance topic, Scott Ballentine.
What’s New
New news for CustomPac removal date, which has been extended past January 2022. The reason was to accommodate
the desired Data Set Merge capability in z/OSMF which customers needed. For the new withdrawl date, it is planned to be announced in 2Q2022.
Mainframe - Only in V2.5
This topic was looking at some new functions that are only in z/OS V2.5.
Data Set File System, planned to be available in 1Q 2022.
Dynamic Change Master Catalog
RACF data base encryption has a statement of direction.
Increase z/OS Memory limit above 4TB to 16TB.
More Concurrently ”Open” VSAM Linear Datasets. Db2 exploits with Apar PH09189, and APAR PH33238 is suggested.
ISPF Updates to ISPF in support of PDSE V2 member generations, and SUBMIT command to add an optional parameter SUBSYS.
Access Method Services - IDCAMS - DELETE MASK has two new options TEST and EXCLUDE
z/OS Encryption Readiness Technology zERT
There’s a lot of other stuff rolled back to V2.4
Performance - What's the Use? - with special guest Scott Ballentine
This discussion is a summary from a joint presentation on Usage Data and IFAUSAGE
The topic is motivational because customers can get a lot of value of out this usage data, and understand the provenance
of IFAUSAGE data.
A macro vendors or anybody use can use to show which products are used and how. It can show names: Product Vendor, Name, ID, Version, Qualifier,
Show numbers: Product TCB, Product SRB, FUNCTIONDATA
The data is ostensibly for SCRT, which is fed by SMF 70 and SMF 89
Scott talked about encoding via IFAUSAGE, appears in SMF 30 and 89-1
SMF 89-1: Software Levels query, Db2 / MQ subsystems query
SMF 30: Topology (e.g. CICS connecting to Db2 or MQ), Some numbers (Connections’ CPU)
Both SMF 30 and 89: FUNCTIONDATA
Examples were mentioned that might inspire developers to think about how they code IFAUSAGE
Hope is developers will delight customers by using IFAUSAGE right, and customers will take advantage in the way shown with reporting examples.
Topics - Choices, Choices
This topics is about how to choose a language to use for which purpose. Different languages were discussed for different needs.
Use Case: Serving HTML?
Host consideration: Running on e.g. laptop?
Host consideration: Running on z/OS?
Overall lesson: Choose the language that respects the problem at hand.
On the blog
Marna's blog is here
Martin has quite a few new blog articles here
So It Goes
36 min
April 20, 2021Episode 29 "Hello Trello"
This episode is about how to be a better z/OS installation specialist, z/OS capture ratios, and a discussion on using Trello. We have a special guest joining us for the performance topic, Miroslava Barahona Rossi. Long show notes are found here .

Mainframe - Being a Better Installation Specialist
"Better" here means lessons learned, not competing with people. "Installation Specialist" might just as well have used "System Programmer" or another term.

There's definitely a reason to be optimistic about being a person that does that Installation Specialist or System Programmer type of work:

There will always be a need for someone to know how systems are put together, how they are configured, how they are upgraded, and how they are serviced...how to just get things to run.

Consider the new function adoption needs too. There are so many "new" functions that are just waiting to be used.

A really good installation specialist would take information they have and use it in different ways.

Knowing parmilb really well.

You can't be better by only doing things yourself, no one can know everything. You've got to work with others who are specialists in their own area.

Last but not least, learn how to teach yourself. Know where to find answers (and that doesn't mean asking people!). Learn how to try out something on a sandbox.

Performance - Capture Ratio
Our special guest is Miroslava Barahona Rossi, a technical expert who works with large Brasilian customers.

Capture Ratio - a ratio of workload CPU to system-level CPU as a percentage.

Commercial considerations when billing for uncaptured cycles. You might worry something is wrong if the capture ratio is low.

Reasonable value is usually 80 - 90. Seeing more like 85 - 95 these days. It has been improved because more of I/O-related CPU is captured.

Summary:

Don’t be upset if you get a capture ratio substantially lower than 100%. That's normal.

Understand your normal. Be aware of the relationship of your normal to everybody else’s. But, be careful when making that comparison as it is very workload dependent.

Understand your data and causes. See if you can find a way of improving it. Keep track of the capture ratio over the months and years.

Topics - Hello Trello
Trello is based on the Kanban idea.

Why are we talking about Trello? We moved to it for high level podcast planning. Template used for hatching new future episodes. We move cards around sometimes between episodes.

Marna uses it to organise daily work, with personal workload management and calendaring. But it is not a meetings calendar.
Probably with Jira will be more useful than ever. We'll see.

Martin uses it for team engagements, with four lists: Potential, Active, Dormant, Completed. Engagement moves between lists as it progresses

Martin's blog
Marna's blog
So It Goes.
1 hr
March 02, 2021Episode 28 "The Preview That We Do Anew"
This episode is about several of the z/OS V2.5 new functions, which were recently announced, for both the Mainframe and Performance topics. Our Topics topic is on Martin's Open Source tool filterCSV. Full long show notes are here.
We have a guest for Performance: Nick Matsakis, z/OS Development, IBM Poughkeepsie.
Many of the enhancements you'll see in the z/OS V2.5 Preview were provided on earlier z/OS releases via Continuous Delivery PTFs. The APARs are provided in the announce.
If you use FTPS for your IBM software electonic delivery, a change is taking place on April 30, 2021. We strongly recommend you use HTTPS instead, but if you still want to use FTPS see IBM software electronic delivery change - take notice!
Mainframe - Selected z/OS V2.5 enhancements
IBM will have z/OS installable with z/OSMF, in a portable software instance format! z/OS V2.4 will not be installable with z/OSMF, and z/OS V2.4 driving system requirements remain the same. z/OS V2.5 will be installable via z/OSMF, so that is a big driving system change.

Learn z/OSMF Software Management at this website.

Notification of availability of TCP/IP extended services

Workload Manager (WLM) batch initiator management takes into account availability of zIIP capacity

Change the Master Catalog without IPL

IDCAMS DELETE mask takes TEST and EXCLUDE.

IDCAMS REPRO moves I/O buffers above line.

New RMF Concept for CF data gathering

RMF has been restructured, but all the functions are still intact. z/OS V2.5 RMF is still a priced feature.
Performance - zCX enhancements
zCX is important for co-locating Linux on Z containers with z/OS.

Popular use cases can be found here and in the Redbook here. Another helpful source is Ready for the Cloud with IBM zCX.

zIIP eligibility enhancements

New enhancements include support 1 MB and 2 GB large pages (still fixed) for backing guests.

Guest memory is planned to be configured up to 1 TB

Another relief is in Disk space limits

Monitor and log zCX resource usage of the root disk, guest memory, swap disk, and data disks in the servers job log.

zCX resource shortage z/OS alerts to improve monitoring and automated operations.

SIMD (or Vector). SIMD is a performance feature, and can be used for analytics.

Nick's presentation (with Mike Fitzpatrick) is here.
Topics - filterCSV and tree manipulation
Mindmapping leads to trees. Thinking of z/OS: Sysplex -> System -> Db2 -> Connected CICS leads to trees.

Has very little automation of its own. But crucially you can mangle the CSV file outside of iThoughts, which is what filterCSV does.
filterCSV is a python open source program that manipulates iThoughts CSV files, colouring CICS regions according to naming conventions

So it goes.
50 min

About Mainframe, Performance, Topics Podcast

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Martin Packer (Principal z Systems Investigator) and Marna Walle (z/OS Development) are two IBMers talking about whatever z/OS topics come to mind. Often guest experts weigh in on current…

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Mainframe, Performance, Topics Podcast

Mainframe, Performance, Topics Podcast episodes

About Mainframe, Performance, Topics Podcast