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Mainframe, Performance, Topics Podcast
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Mainframe, Performance, Topics Podcast
Author: Marna Walle
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© Marna Walle
Description
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 technologies. This podcast will give you timely, interesting, and entertaining z/OS topics. Each episode comprises a “Mainframe” item, a “Performance” item, and “Topics” which is anything Martin or Marna care to talk about, which might or might not be related to their jobs. So it goes…
35 Episodes
Reverse
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
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
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
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
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
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.
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.
Episode 27 "And Another Thing" show notes. Long show note are here.
Follow up
Additional System Recovery Boost enhancements:
Sysplex partitioning recovery: Boosts all surviving systems in the sysplex as they recover and takes on additional workload following the planned or unplanned removal of a system from the sysplex.
Two more portable software instances: Db2 and IMS added to Shopz on Aug 20, 2020, in addition to CICS (Dec 2019).
ASK MPT
Martin was asked about which systems in a System Recovery Boost Speed Boost situation get their GCPs sped up to full speed.
Mainframe - Trying out Ansible for driving z/OSMF Workflows
Marna's been learning about Ansible and how it can drive z/OSMF work. So far with z/OSMF Workflows, from ansible-galaxy collection for ibm.ibmzoszosmf
Needed lots of assistance from two gracious Poughkeepsie system testers (massive thanks to Marcos Barbieri and Daniel Gisolfi !!)
Learning about an Ansible
Encountered two kinds of problems:
Security issues connecting the Linux environment to a large Poughkeepsie System Test z/OSMF environment
Workflow-related: duplicate instances when part of the playbook ran ok, and selecting an automated workflow.
Performance - So You Don't Think You're An Architect?
Brand new presentation for 2020, builds on the “who says what SMF is for?” slide in "How To Be A Better Performance Specialist"
Presentation talks about 3 layers
The Top Layer - Machines, Sysplexes And LPARs
The Middle Layer - Workloads And Middleware: Spikes, Restarts, Cloning, Topology, Software Levels
The Bottom Layer - Application Components: Db2 and MQ Accounting Trace, DDF topology, data sets
Fulfilling the definiton Of Architecture? Understand what's really going on and valuable to system architects
Topics - Notifications
They are unsolicited messages appearing on the device, generally interruptions whether wanted or not.
Examples of what is received and where/
IFTTT still a favorite of Marna's, mentioned in Episode 23 “The Preview That We Do” Topics topic. Martin just subscribed to Premium, but at a low-ball price.
How do you manage them to reduce their number.
An advanced topic is how you can generate your own
On iOS the Pushcut app: a webhook from eg IFTTT can cause a notification
On Android we have MacroDroid.
Customer requirements
Customer Requirement 138729 : z/OS Console message help support JES2 messages
IBM response: This RFE has been delivered via APAR PH24072 at end of June 2020. It's available on both V2R3 and V2R4. The JES2 message prefix such as $ can be setup in "Configure Message Help" dialog in z/OSMF Console UI.
On the blog
Martin's blog posts are here
Marna's blog posts are https://blog.share.org/Article/tag/marnas-musings
So it goes.
Here are the show notes for Episode 26 "Sounding Board". The show is called this because it relates to our Topics topic, and because we recorded the episode partly in the Pougkeepsie recording studio where Martin sounded zen, and partly at home.
What’s New
APAR PH21919: NEW FUNCTION - WORKFLOW SUPPORT SAVE JOB OUTPUT
PTF Numbers are UI68359 for 2.3 and UI68360 for 2.4
APAR OA56774 (since 2.2) Provides new function to prevent a runaway sysplex application from monopolizing a disproportionate share of CF resources
Not based on CF CPU consumption. Is based on deteriorating service times to other structures - which you could measure with SMF 74-4 Coupling Facility Activity data.
Mainframe - z15 FIXCATs
IBM.Device.Server.z15-8561.RequiredService: Absolute minimum needed to run on a z15. Usually intent is to keep these PTFs to a minimum - and keep the number of PTFs relatively constant. <<Correction: SRB z15 GA1 is here, not Exploitation!>>
IBM.Device.Server.z15-8561.Exploitation: Needed for optional functions, and you can decide when you want to use them. This PTF list could grow - if we add new functions
IBM.Device.Server.z15-8561.RecommendedService: Usually to fix a defect that is found but haven’t risen up to required. Might want to run an SMP/E REPORT MISSINGFIX to see what’s in this FIXCAT. Might install some, all, or none of the fixes. Might want to be more selective. Based on how much change you want to encounter, versus what problems are fixed
By the way there are other FIXCATs you might want to be interested in for z15, e.g. IBM.Function.SYSPLEXDataSharing
Performance - DFSORT And Large Memory
A very special guest joins us, Dave Betten, former DFSORT performance lead.
Dave talked about DFSORT memory controls
DFSORT has historically been an aggressive user of memory
Installation defaults can be used to control that
But the EXPOLD parameter needs special care - because of what constitutes "old pages", which aren't actually unused.
DFSORT Tuning Guide, especially Chapter 3
Dave talked about how handy rustling up RMF Overview Reports can be, with several Overview conditions related to memory.
Most of the information in this topic is relevant to LPARs of all sizes
Topics - Update on recording techniques
Recording of podcast - still using Skype to collaborate
Production - Editing - Moved to Ferrite on iPad OS
Publishing - same process as before, but on a new publisher!
Customer requirements (assume usual disclaimer)
RFE 139477 “Please include the CPU Time Limit for a Job/Step in SMF Type 30”
After the fact - End of step looks useful. Could run query comparing to actual CPU time, then track to see if ABEND is on the horizon
“ As it happens ” - Would like on the SMF Interval as well as Step End records. May not need the SMF information if vendor and IBM tools already do it today.
On the blog
Martin's has blog posts since the last episode.
Marna has three on her blog here.
So it goes...
Here are the show notes for Episode 25 “Flit for Purpose”. The show is called this because it relates to our Topic, and also can be related to our Mainframe topic (as a pun for “Fit for Purpose”).
Mainframe Topic: Highest highlights of z/OS V2.4 and z/OS on z15
Highlight 1: zCX
Highlight 2: z/OSMF
Lots of z/OSMF enhancements that have arrived in z/OS V2.4, and the good news is that most of them are rolled back to V2.3 in PTFs that have been arriving quarterly.
Security Configuration Assistant: A way within z/OSMF to validate your security configuration with graphic views, on the user and user group level. Designed to work with all three External Security Managers!
Available back to V2.3 with APAR PH15504 and additional group id enhancements in APAR PH17871
Diagnostic Assistant for z/OSMF : A much simplier way to gather the necessary information to need for a Service person to perform debug for your z/OSMF problem.
Hightlight 3: SRB on on z15: System Recovery Boost :Speeds up your shutdown for up to 30 minutes and speeds your re-IPL for 60 minutes, with no increase to your rolling four hour average.
Performance Topic: z15 from chip design on upwards
Disclaimer: personal view, not from Development or Marketing. Marna and Martin were talking about the z15 Chip design – and we thought those observations might be useful to include in the Performance topic.
Two traditional levers were raising clock speed or shrinking the feature size.
GHz and nm aren’t the be all and end all. Look at chip design.
Start with a similar sized CP chip and putting more on it. It helped to get rid of the Infiniband-related circuits, and some layout enhancements.
At the top end there are up to 190 characterisable cores, coming up from 170. This can give us a fifth drawer – which is quite important.
Topic: How To Do A Moonlight Flit
This topic is about moving one’s social output, in particular blogs and podcast series. Martin’s blog had to move, because the IBM developerWorks blog site is being shut down. Martin's blog has had to move, as well as this podcast.
Immediately people might worry about Request For Enhancements being affected , and it is not.
Martin and Marna discuss important aspects to consider when moving your social media.
You must consider all the pieces when do you the most.
You must also try to redirect your audience.
Contacting us
You can reach Marna on Twitter as mwalle and by email.
You can reach Martin on Twitter as martinpacker and by email and blogs at blog.
Here are the show notes for Episode 24 “Our Wurst Episode”. The show is called this because we both attended the IBM TechU in Berlin, Germany, and our Topics topic is our trip report.
Mainframe Topic: CICS ServerPac in z/OSMF
IBM’s first delivery on new installation strategy, will be with CICS and associated SREL products. This is the first of many (really, all).
Choice on new installation strategy or old during ShopZ ordering.
We encourage making the z/OSMF choice, as that is consistent between IBM and other vendors, and is intended to be easier.
Infrastructure already available in continuously delivery PTFs, and rolled back to z/OS V2.2. This makes the driving system have the proper infrastructure so anybody can package and deliver that way.
All software that you ordered as a ServerPac, and installed either way, will give you the same (or hopefully better) equivalent installation.
There is an IBM Statement Of Direction that this installation choice is coming, but we do not have an exact date yet.
For other software ISVs, they can exploit the new z/OS installation strategy whenever they are ready.
Prepare now by becoming familiar with z/OSMF Software Management and Workflows
Performance Topic: DB2 And I/O Priority Queuing
Follow on from Screencast / Martin's Blog post topic:, "Screencast 12 – Get WLM Set Up Right"
Recent talk has been about whether to turn off I/O Priority Queuing in WLM.
Service classes with DB2 subsystems in are heavily I/O Sample oriented, which is unusual among service classes in a system.
Means access to CPU is not properly managed, as CPU & zIIP samples few, relative to I/O samples. Reminder: Most of DBM1 is now zIIP-eligible.
Can achieve goal even with lots of delay for zIIP or CPU, but that’s definitely not what you want.
You don’t want to just turn off WLM I/O Priority Queuing, as it’s sysplex-wide, it might affect other work that needs it, and Db2 might actually need it.
First you need a reasonably achievable goal for the service class. Make sure you’re more or less achieving the existing goal.
Second, calculate what the velocity achieved would be without I/O priority queuing .
You should evaluate or adjust the goal attainment, but that is BAU. Changing WLM always needs some care.
Topics: Berlin Trip Report May 20-24
We both attended IBM Z TechU in Berlin, and got to see each other.
Marna had about six sessions.
The SMP/E Rookies session had fabulous attendance – 44. Some were more experienced, but most were not.
z/OSMF had good attendance too, about 82. More are interested in this topic, especially if you compare to just a couple of years ago.
Best attended was the z/OS V2.4 Preview, with about 150 people. There was excellent interest in what is coming in the new release.
Marna did her own poster to help with z/OSMF configuration, and several people came by to chat.
Both Marna and Martin shared a poster about this podcast. We helped with getting one person a podcast app (on each platform), and a subscription to this podcast.
Martin had five sessions. One was co-written with Anna, “2 / 4 LPARs” Two were solo efforts: Parallel Sysplex Performance Topics, and Even More Fun With DDF.
Contacting Us
You can reach Marna on Twitter as mwalle and by email.
You can reach Martin on Twitter as martinpacker and by email and blogs at blog.
Here are the show notes for Episode 23 “The Preview That We Do”. The show is called this because we talk about the newly previewed z/OS release, V2.4, in the Mainframe section. This is our 24th episode too! How convenient!
Mainframe: z/OS V2.4 Preview
“z/OS Container Extensions” (zCX) zCX Information
z/OS Upgrade Workflow, no book
More in Pervasive Encryption
zFS enhancements
MCS logon passphrases
Biggest question one may have: what level of HW will z/OS V2.4 IPL on? z/OS V2.4 will run on zEC12/BC12 and higher.
Performance: Coupling Facility Structure Duplexing
Two types of CF structure duplexing:
User-Managed: Only DB2 Group Buffer Pools (GBP)
System-Managed: e.g DB2 IRLM LOCK1 Structure
Structure performance matters:
User-Managed not an issue.
System-Managed matters.
Asynchonous CF Structure Duplexing Announced October 2016
Important considerations if Async CF Duplexing good all the time:
People make architectural decisions and this should not be a leap in the dark .
Ideally should be established with a little testing, with testing as close to production behaviors as possible.
Generally it’s good for you.
Configuration: Format couple data set, put into service, and then REALLOCATE. Again speaks to planning and testing.
The main event for this item is SMF.
SMF 74-4 Coupling Facility Activity data, primarily interested in structure-level, especially for structure duplexing of any kind. Though CF to CF pathing information also available.
New Async CF Duplexing instrumentation APAR OA49148
Early days of Async CF Duplexing despite having been announced in 2016. Martin has been using a customer’s test data, and would like to build experience. Only a portion of this new SMF 74-4 data is surfaced in RMF Postprocessor reports.
z/OSMF Sysplex Management can help visualize and control the Sysplex resources. This function to help with control is in PI99307: SYSPLEX MANAGEMENT APPLICATION ENHANCEMENTS TO MODIFY SYSPLEX RESOURCES.
Topics: Smart home thermostats
Marna just installed two Nest thermostats, one in each zone (of a three-zone house). Is sharing data with Nest, and presumably whoever owns Nest currently (Google). Instrumentation benefit is having an app in which she can look at what is happening at home, when away, and control it too.
There are excellent graphs on what has been used (hours of heating, cooling) in the app.
Martin doesn’t have a smart home thermostat, but does have a remote oil tank sensor to determine how much oil is left. This sensor feeds back into a device in the house, and connects to an app on his phone.
It costs 5 GBP a month, but is unsure yet if it is worth it.
Contacting Us
You can reach Marna on Twitter as mwalle and by email.
You can reach Martin on Twitter as martinpacker and by email and blogs at blog.
Here are the show notes for Episode 22 “Great App-spectations”. The show is called this because we talk about app expections in our Topics topic.
Mainframe: PI99365 Two enhancements in z/OSMF Operator Consoles
Support for “sticking” WTOR and held messages on the top of the console area
Visible EMCS console name
View WTOR and HOLD messages in a separate window
Visible console name part
Overall: These two function areas help you manage your z/OSMF operator consoles better.
Performance: Paging Subsystem Design in an age of Virtual Flash
Performance: Paging Subsystem Design in an age of Virtual Flash
Question from customer about need for paging space if Flash installed , which was answered in Martin’s blog post, but there is more thinking about this.
Look at the paging subsystem design in the round, with two flavours of Flash: FlashExpress (PCIE) and VFM
Design standpoint ideally as if no Flash
Paging subsystem design: Two main considerations: Space and Performance
Come together in “30% Contiguous Slot Allocation Algorithm breakdown” rule of thumb
Instrumentation
RMF SMF 71, also covers memory. Flash treated like ordinary paging device.
RMF SMF 74-10 in OA50761
Wrap up: Paging subsystem design still worthy of care, and establish whether risk of Flash or Virtual Flash warrants conservative configuration of paging subsystem.
Topics: Anatomy Of A Great App
“App” here means “third party software” but we’ll say app for short
Highly biased on expectations in iOS, as Martin is a power user.
Marna gave the Android perspective
z/OS perspective was discussed.
Conclusion: Think about more than just what your app is supposed to do. Nobody wants software whose function they like but they hate using. It is way too easy to uninstall an app (or have hundreds of them and not use them).
Keep to the “Principle of least astonishment”.
Contacting Us
You can reach Marna on Twitter as mwalle and by email.
You can reach Martin on Twitter as martinpacker and by email and blogs at blog.
Here are the show notes for Episode 21 “Fits and Starts”. The show is called this because we talk about fitness devices, and the Performance topic that had work submitted after a one minute hiatus.
Mainframe: SMF Recording of APF Modifications
Post-IPL dynamic APF changes are reflected in SMF 90 Subtype 37. A lot of the function is in z/OS V2.2, with these fields in the SMF record:
Function:
Add, Delete, DynFormat, StatFormat
Was the update via SETPROG, SET PROG, CSVAPF
Parmlib member suffix for the SET PROG case, ...
Triggers when post-IPL APF changes dynamically: PROGxx: APF ADD …or APF DELETE … SETPROG APF,ADD,… or SETPROG APF,DELETE,…
Ensure to collect by setting in SMFPRMxx type 90 subtype 37 record
Presumably there’s not much overhead, as it will be produced when changes happen (which is probablyl not often).
Auditors will probably want this
Performance: An interesting Db2 DDF case
Central to Martin’s DDF work is some analysis code to process SMF 101 DB2 Accounting Trace.
A customer complained their DDF application stopped dead one evening – for 1 minute. It was an application serviced by a 3-way Datasharing group. The customer sent SMF 101 data from all 3 members for 3 hours around the stoppage, and for 3 hours the previous evening for a presumably “good behaviour”.
Martin plotted application statistics at a one second interval level. It showed a 40-second stoppage the evening they hadn’t complained, making the 1 minute threshold interesting as a number.
Martin “zoomed in” to a much shorter time range . When transactions started again they were elongated, and it that was due to the clustered arrivals in clearing the backlog.
The best theory is something external stopped transactions arriving.
Further he thought there could be “near misses” many times, just short of the 1 minute mark. After transactions started coming again there were spikes in transactions arriving every minute. The speculation is this might be the middle tier doing something on a 1 minute basis: Maybe retries of some sort?
Topics: Fitness Tracking
Marna uses a Fitbit Charge 2.
Key features: sleep analysis, step counts, heart rate.
Fitbit app for the Android: calculates floors, miles, calories, sleep analysis, across timescales – day, month, overall, etc and compares with age bracket.
Martin uses an Apple Watch, and used to have a Fitbit. He wanted the Watch for other reasons: for health a few months ago, and all of the above – except for sleep tracking.
Marna gets employer incentives, to help with health care cost reduction.
Martin has been successful, as he hasn’t failed to close his rings for 3 months, for the Apple Watch. This makes him obsessive. Uses iOS Overcast podcast player to send podcast episodes to the watch. Runs with just the watch and AirPods. Listening to podcasts keeps me going – whether running or walking. He has lost a considerable amount of weight! Cardiac situation much better, lowered resting heart rate, faster recovery from exercise, and clothes fit better.
Contacting Us
You can reach Marna on Twitter as mwalle and by email.
You can reach Martin on Twitter as martinpacker and by email and blogs at blog.
Here are the show notes for Episode 20 "Two Is One And One Is None". The show is called this because our Topic topic is trying to figure out how to archive family photos and videos.
Mainframe: zFS Shrink, Only in z/OS V2.3
A system command for reducing the size of a zfs file system. Not be confused with compressing files within a file system. Found on zfsadm shrink. You specify a target size with the size option, gives _final_ size in KB, gets rounded to 8K boundary .
-noai option: means no active increase. A file system is being accessed, might need additional blocks over the shrink size given. so it can be "actively increased" by default.
During a shrink a scan occurs to determine what blocks must move...longest part of the operation. Blocks are moving from the portion to be released, into the portion that is to remain.
After Blocks are moved, and then space is release - in which it will be briefly quiesced. Applications do not need to be stopped when doing a shrink.
Reminder to use aggrgrow to increase the size of the filesystem. Monitor with SMF 92 subtype 50 for both grow and shrink events. Subtype 59 for # of I/Os and rate, but might occur too often, so use it wisely.
Performance: CPENABLE and HiperDispatch
I/O ends with an Interrupt. Needs to be handled by a processor, and needs to be handled in a timely way. Can be handled with Test Pending Interrupt (TPI). If test true this CP handles pending interrupt. If false then handled by normal interrupt handling. If many TPI successes suggests queue build up. Trade off between timeliness and processor efficiency
There’s a trade off between timeliness and processor efficiency. The CPENABLE parameter’s values manage this trade off. There are two values: if TPI% below first disable a processor from handling I/O interrupts, and if TPI% above second enable a processor to handle them.
Without Hiperdispatch, access to CPU is smeared across online processors, as the LPAR’s weight is evenly spread across its logical processors. Without Hiperdispatch it is recommended that CPENABLE be set to 0,0 which allows all processors to handle interrupts.
Overall this topic shows I/O Interrupt Enablement is a topic worthy of consideration to get timeliness vs efficiency right – particularly in the Hiperdispatch era. Also that the instrumentation really helps.
Topics: Archived Family Information
Talking about personal and family information: photos, audio, and video only. Not writings. Some serious questions:
“What happens when I’m dead?” Facebook, for one, has a protocol. Google has a protocol.
Ideally write a will and tell family how to handle material.
Will anyone else care about the material?
“What about Big Brother” : Everyone has something to hide, it’s about trusting the service provider
“Who owns the material?” and do you care?
Contacting Us
You can reach Marna on Twitter as mwalle and by email.
You can reach Martin on Twitter as martinpacker and by email and blogs at blog.
Here are the show notes for Episode 19 "You've lost that syncing feeling". The show is called this because our Topic topic is about losing the Xmarks URL synchronization tool.
Mainframe
Our "Mainframe" topic discusses moving from V4 to V5 zFS, prompted by a user comment that had a very positive experience.
The old version for zFS was V4. V5 gives you a directory using a tree structure for faster searching. This should be faster than a naive linear search approach.
To take advantage of this, you need to convert from old V4 format to V5.
You can convert: offline with _IOEFSUTL_, online with _zfsadm convert_ , _IOEFSPRM CONVERTTOV5=ON_ , and on _MOUNT_ - you choose.
Steps are: ensure fully at V2.1, set _IOEPRMxx format_aggrversion=5_ for new file systems, set _IOEPRMxx change_aggrversion_on_mount=on_ for fast safe file system switch to V5, determine if you want _IOEPRMxx CONVERTTOV5=ON_ for one-time switch on directory access. Delay is expected!
If cannot tolerate one-time delay, use _MOUNT CONVERTTOV5_ to selectively determine most benefit, on large directories and those highest used (_F ZFS,QUERY,FILESETS_)
Use _zfsadm fileinfo_ to see a directory version, use _zfsadm aggrinfo -long_ to look at all the file systems.
Performance
Our Performance topic is a survey of Licence-Related Instrumentation. Most shops are very conscious of software costs. Martin discusses the instrumentation portion.
SMF can help you: System-Level SMF 70 give you the rolling 4 hour averages, defined capacity and group capacity information, and high-level CPU . System-Level SMF 89 gives you more detailed information on licencing: product usage names, and CPU. Service Class Level SMF 72-3 gives you Service Units (SUs) consumed on zIIP, on general purpose CP, and zIIP-Eligible on general purpose CP.
Mobile SUs one category and total SUs another
Resource consumption in general . Address Space Level SMF 30 gives you a usage data section for topology and for CPU in a product sometimes.
Container-Based Pricing introduces new metrics: 70-1, 89, 72-3, and Tenant Classes and Tenant Resource Groups explicitly documented.
Topics
Our podcast "Topics" topic is about Marna losing a handy and simple URL sync tool, XMarks. Xmarks used to let you save bookmarks between browsers with other cool capabilities. It was discontinued on May 1, 2018. XMarks was a plug-in to browser, logon, sync, and they were there! With multiple profiles.
Here are some https://techwiser.com/xmarks-alternatives/ ? :
NetVibes: better for rss feeds and dashboard seem to be its strength.
Google Bookmarks syncs URLs; But still only for Firefox and Chrome. Gmarks will connect to google servers.
Modern browsers can fake the User Agent to look like IE
Diigo (at https://www.diigo.com/toolsw) ith a toolbar: not used it. Pricing plans, sharing URLs. A bit too heavyweight/
The promising one is called Raindrop (at https://raindrop.io/) for Chrome, FF, and Safari. Just started trying it out. Works between Windows and Android!
Safari / Mobile Safari use iCloud syncing and work out of the box. But if you share an Apple ID, watch out!
Contacting Us
You can reach Marna on Twitter as mwalle and by email.
You can reach Martin on Twitter as martinpacker and by email and blogs at blog.
Here are the show notes for Episode 18 "What we won't have in common anymore". The show is called this because our Mainframe topic is about some removals in common storage planned for the release after z/OS V2.3.
Mainframe
Our "Mainframe" topic discusses a future planned removal coming in the release after z/OS V2.3.
Four items actually form what we've titled "User Key In Common Storage Removal". This has been outlined in a Statement of Direction, and is documented in the z/OS V2.3 Migration Workflow and book.
ALLOWUSERKEYCSA in DIAGxx will be treated as NO.
Removal of support for obtaining User Key CSA
Can’t change ESQA storage to User Key
Can’t create a SCOPE=COMMON Dataspace in User Key.
New capabilities with OA53355, which is at z/OS 2.1 and above:
SMF 30 has been enhanced to identify jobs/steps that use user key common storage.
SLIP Trap Capability. Single slip trap covering the removed items.
A new z/OS Health Checker for z/OS health check, ZOSMIGV2R3_NEXT_VSM_USERKEYCOMM..
Performance
Martin talked about what’s in a data set name and this topic is about getting insight by parsing data set names. His reporting code, which processes SMF 14 (OPEN for read) and SMF 15 (OPEN for write) records, bolds data set qualifiers (or segment names) if they match any of a bunch of criteria. Now, new criteria have been added to investigating data set names.
The new criteria are job step name, dates (in lots of formats), job step program name, “SORT” in the qualifier, and system SMFID.
While the code doesn't see "partner" job names (for instance, where one writes to a data set and the partner reads from the data set),
those could be detected using the Life Of A Data Set (LOADS) technique, which we can talk about more one day.
And surely there will be more interesting finds in other customers' data set names. As they are stumbled upon the code can be enhanced to learn these new tricks - as Martin refactored it to make it easier to add new criteria.
Topics
Our podcast "Topics" topic is about two cheap and fun pieces of hardware Martin has been playing with: Raspberry Pi and Arduino.
Arduino is more hardware oriented. It is an open source hardware board. It is a microcontroller you download small programs to from e.g. a PC, written in a flavour of C. It is optimised for driving electronics, e.g. on a breadboard and boards you plug into the top of the Arduino (called shields).Martin has three Arduino shields: An SD Card reader/writer, a 7-segment display, and graphical LCD display.
Raspberry Pi is more for software. It is a small cheap computer on a card.Martin's has 4 USB ports, HDMI, Ethernet, Wifi, and runs Raspbian. You can run other builds. He bought an HDMI monitor for it (HP 27es).He also found a Logitech K780 keyboard and a Logitech M720 mouse. Both of these can be switched instantaneously between 3 computers, connected via Bluetooth or USB.
Contacting Us
You can reach Marna on Twitter as mwalle and by email.
You can reach Martin on Twitter as martinpacker and by email and blogs at blog.
Here are the show notes for Episode 17 "Two Good, Four Better?". The show is called this because our Performance topic is about aspects of whether more LPARs in the same CECs in a sysplex is better or worse.
Mainframe
Our "Mainframe" topic discusses the addition of a new parmlib member for RACF, IRRPRMxx.
It replaces ICHRDSNT (the RACF Data Set Name Table), and ICHRRNG (the RACF Range Table). These previously could be provided as usermods, maintained as assembler source.
If you use both, the load modules for ICHRDSNT and ICHRRNG and the IRRPRMxx parmlib member, the parmlib member takes precedence.
IRRPRMxx is found at IPL within IEASYSxx RACF= statements. You can have up to three members. ICHRDSNT replaced by DATASETNAMETABLE statement, and ICHRRNG replaced by RANGETABLE statement in the parmlib member. Complete syntax is found here.
You don't need to code the new IRRPRMxx from scratch, you can use a nicely provided REXX exec to convert from memory on what you are currently using, or from a load module on DASD with
DSNT2PRM. Be careful, though, as any RVARY commands might change settings won't be reflected. This tool is informal and off the web, and it can be run pre-V2.3 just to see what it produces.
Then, when you're ready to use your real IRRPRMxx members, just update your IEASYSxx and IPL.
Performance
Martin talked about whether 2 LPARs (on 2 CECs) or 4 LPARs (on 2 CECs) is better.
This is related to some trends, but it's a big subject.
There are tradeoffs between 2 vs. 4. Better availability with 4, but would it perform better or worse? It might be better if you get to a state where each LPAR is contained in a single drawer (on z13 or z14). (At least two customers he knows does this.) There is more PR/SM overhead with more LPARs, which was discussed in a 1990 Washington Systems Center Orange book ("PR/SM Performance in LPAR Mode", ZZ05-0453).
Also the topic of memory duplication, with more DB2 images. CICS and MQ would similarly have memory considerations too. There might be some scope for consolidation of DB2s.
Operational and software considerations need to be thought through. How much harder would it be to manage it, and also keep the software up to date across more images? Of course, much of the thinking would already have been done for 2-way.
Topics
Our podcast "Topics" topic is a follow up and a short discussion on what to do if your wifi isn't performing as you wish.
It's been a year since Marna's son built his "gaming" personal computer. She asks him about what has gone well with it, and what he might save for in the future.
One thing that has been a problem is the wifi signal in the house. It is not consistently strong, and he would like an ethernet connection directly into the computer.
That isn't happening (with a cord down the hallway), so a different solution was found: Powerline Ethernet solution, which plugs into two electric outlets.
This was less than $100 and is working well. Other solutions do exist, but this cost effective one has been this gamer's delight.
Contacting Us
You can reach Marna on Twitter as mwalle and by email.
You can reach Martin on Twitter as martinpacker and by email and blogs at blog.
Here are the show notes for Episode 16 "Chapter and Worse". The show is called this because our Topics topic is about adding chapter markers (and pictures!) to our published MP3 file. We hope those of you that can see them enjoy them.
Mainframe
Our "Mainframe" topic discusses a new z/OS V2.3 function, Coupling Facility Encryption, with Mark Brooks,
Sysplex Design and Development. Mark talked about this latest capability in Sysplex, which has been
getting a lot of attention as part of the larger Pervasive Encryption direction.
Mark explained that CF Encryption means that the customer's data is encrypted by XCF
in z/OS, sent along the link as encrypted, and stored as encrypted on the Coupling Facility.
z/OS sysprog needs to set it up by:
using new keywords on CFRM policy on a structure by structure basis
putting it in your CFRM couple data sets, and the policy change will be pending
rebuild the struture (to get it from unencyrpted to encrypted)
DISPLAY XCF structure commands can be used to see what the policy
has, what the structure currently is, and the form of encryption used.
List and Cache structures contain customer sensitive data, the XCF control
information will not be encrypted because it is not sensitive customer data. Lock
structures don't contain sensitive customer data, and are not encryptable.
Tooling:
zBNA looks at new SMF data, so that you can see the amount of data transferred to the CF. From there, you could judge the cost of doing the encryption.
SMF 74 Subtype 4 records contain the new information on the amount of data, via measurement APAR OA51879 on z/OS
V2.2. Planning can begin on z/OS V2.2 with this APAR.
For more information, see the z/OS Setting Up a Sysplex.
Performance
Martin talked about MSU-related CPU fields for doing software pricing analysis. Some of these fields are used by SCRT in support of the new Mobile function. Most notably the fields cover:
Mobile Workload Pricing (MOBILE), using a new WLM mechanism, .
CATEGORYA and CATEGORYB: These are just placeholders for any future additional pricing options that come about.
Container Pricing is another pricing model, ....., and maybe another topic on that later.
The overall idea: Be aware of the new fields that you will be analysing. These fields are available at two levels:
At the System level, as Rolling 4 Hour Average numbers - in SMF 70 Subtype 1.
At the Service Class Period level, as interval-based numbers - in SMF 72 Subtype 3.
Topics
Our podcast "Topics" topic is about adding chapter markers to the MP3 file for podcast apps. This
makes it nice to skip from one section to another easily. Our podcast has five
sections, each with its own graphic and chapter.
Contacting Us
You can reach Marna on Twitter as mwalle and by email.
You can reach Martin on Twitter as martinpacker and by email and blogs at blog.
Here are the show notes for Episode 15 "Waits and Measures". The show is called this because our Performance topic is about LPAR weights, and because this episode was after a seasonal hiatus.
Mainframe
Our "Mainframe" topic discusses a small new function in z/OS UNIX V2.3: automatic unmount of the version "root" file system in a shared file system environment. Our guest was Barry Lichtenstein, the developer of the function, and he told us all about it:
there is a new BPXPRMxx VERSION statement parameter, UNMOUNT. This means that when no one is using that "version filesystem", it will be automatically unmounted. This is not the default. Syntax here
this function is nice, as it will allow an unused version file system to be "rolled off" when you don't need it anymore. Unused here, means that no system is using it or using any file system mounted under it. z/OS UNIX will do this detection automatically, and unmount not just the version file system, but mounted file systems under it that are no longer used by any systems after an unspecified amount of time.
you can turn this on and off dynamically with a SET OMVS or SETOMVS command. There is DISPLAY command support of it. And perhaps the best news, the health check USS_PARMLIB will see if the current settings don't match the used parmlib specification.
we weren't sure if SMF record 92 would be cut when the unmount happened, but Barry said nothing unique was happening for this function so what happens today is most likely the same behavior. There are messages that are issued in the hardcopy log when the unmounts happen. SMF 90 might be issued for SET changes.
Performance
Martin talked about Weights and Online Engines in LPARs, and Martin again looking at customer information.
Intelligent Resource Director (IRD) changed PR/SM worked:
Dynamic weight adjustment
Online logical engine management (vary online and offline). Shows minimum and maximum weights when changed by IRD.
HiperDispatch: took away logical engine management (and manages it better!), and kept IRD dynamic weight adjustment. With HiperDispatch's parking of engines, no work is directed towards it.
More instrumentation was introduced, such as Parked Time and refined instrumentation on weights (vertical weights, by engine).
Customer situation was that they did their own version of IRD and HiperDispatch: Varying logical engines online and varying weights (not using IRD itself). Martin expected IRD to change weights, but he saw the IRD weight fields were all zero.
Why not let IRD do it? Martin thinks there was something in the customer's mind to control it themselves.
Why not use HiperDispatch? Martin thinks that maybe a subtle difference might be needed, but LPARs should be designed properly.
Topics
Our podcast "Topics" topic was "Video Killed the Radio Star?" and about screencasting. Martin has been trying to post screencasts to YouTube. Here's one.
Contacting Us
You can reach Marna on Twitter as mwalle and by email.
You can reach Martin on Twitter as martinpacker and by email and blogs at blog.
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