27 episodes

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… 

Mainframe, Performance, Topics Podcast Marna Walle

    • Technology

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… 

    Episode 26 "Sounding Board"

    Episode 26 "Sounding Board"

    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.  >
    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...

    • 56 min
    Episode 25 "Flit for Purpose"

    Episode 25 "Flit for Purpose"

    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.

    • 41 min
    Episode 24 "Our Wurst Episode"

    Episode 24 "Our Wurst Episode"

    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.

    • 42 min
    Episode 23 "The Preview that We Do"

    Episode 23 "The Preview that We Do"

    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.

    • 33 min
    Episode 22 "Great App-spectations"

    Episode 22 "Great App-spectations"

    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.

    • 42 min
    Episode 21 "Fits and Starts"

    Episode 21 "Fits and Starts"

    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.

    • 33 min

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