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Capacity, Performance and Systems Investigation
At one level Performance and Capacity Management and Systems Investigation are clearly linked: They share the same data. Or much of it at least. But I think they're linked in another way, too. Over the past few years I've gradually shifted emphasis towards Systems Investigation. But this has only been a slight shift, a "non modo sed etiam" and still only really mainframe. So I'm... [More]
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WLM Velocity - "Rhetorical Devices Are Us"
I'm beginning to look at performance data slightly differently these days... As well as plotting things by Time Of Day (which our tools have done for 25 years) I'm beginning to plot things more directly with load. (Time Of Day is sort of code for With Load but not really - telling a story people can relate to more directly.) The first instance of this "with load" approach was plotting... [More]
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He Picks On CICS
If you think this title is obscure bear in mind the original working title was "Send In The Hobgoblins". 1 When I started to write - actually before the "mind mapping" stage - it was going to be all about inconsistency in the way bits of systems are named. You'll see some of that reflected in the finished article (pun intended) but the post has mostly gone in a different... [More]
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If The Cap Doesn't Fit...
... swear at it. :-) No, I KNOW that's not right - but it's (for me) an irresistibly bad pun. And it's a natural reaction, too. :-) In a recent customer situation I looked at the RMF Workload Activity Report data for a number of service classes. One WLM Sample count was particularly high: "Capped". In fact I look at, with tooling, SMF and the actual field is R723CCCA. (An IBM... [More]
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Data Collection Requirements
Over the years I’ve written emails with data collection requirements dozens of times, with varying degrees of clarity. It would be better, wouldn’t it, to write it once. I don’t think I can get out of the business of writing such emails entirely but here’s a goodly chunk of it. Another thing that struck me is that the value of some types of data has increased enormously... [More]
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Discovering Report Class / Service Class Correspondences
It’s possible I’ve written something about this before:
My blog is so extensive now it’s hard to find out exactly what I’ve written about (and I’m going to have to do something about that). I say “written something ” because I know for sure I haven’t written about the SMF record field I want to introduce you to now. Previously If when you send me... [More]
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Playing Spot The Difference With WLM Service Definitions
A customer asked me to examine two WLM service definition snapshots taken on adjacent days - and discern any differences. This is not a challenge I’ve been set before - and so I expect it’s pretty rare.
But, thinking about it, I reckon it could be quite useful. So they sent me two service definitions, one day apart, and one from months later.
When I say “a service... [More]
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Are You Being Served?
As you will’ve seen in
WLM Response Time Distribution Reporting With RMF I’ve been thinking about WLM Response Time goals quite a bit recently.
And this post continues the train of thought. It’s very easy to think of WLM Service Classes as being self contained.
For many that’s true - and only their own performance numbers need to be considered for us to understand their... [More]
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WLM Response Time Distribution Reporting With RMF
If you’re running a workload with WLM Percentile Response Time goals
take a look at the RMF Service Class Period Response Time Goal Attainment instrumentation.
It’s in the Workload Activity Report but this post is about using the raw data to tell the
story better than a single snapshot (or long-term “munging”) can. (An example of a percentile response time goal is “90% of transactions must end... [More]
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A Simple Graphing Enhancement Makes All The Difference
Once in a while there comes along a simple coding enhancement that really kicks the story forwards.
This post is about just such a simple thing, as I think customer Performance people would benefit from it. Consider the following perfectly ordinary graph heading (and ignore the grottiness of the font if you can). I'd like to draw your attention to the portion if it in the brown box.
That's the... [More]
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Would You Like More WLM Information In DB2 Accounting Trace - And How Would You Use It?
I was lucky enough to be in Silicon Valley Lab for DB2 BootCamp last week. There I ran into a DB2 developer I've worked very successfully with in the past - John Tobler. (He's the guy I look to for questions and issues with DB2 SMF data.) We had a good discussion about something I'd personally like to see in DB2 Accounting Trace - more WLM information - and this post is as a result of this... [More]
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What's In A Name?
This is the post I was going to write before the discussion that led to CICS VSAM Buffering arose. It's about getting more insight into how WLM is set up and performing than RMF Workload Activity Report data alone allows. I recognise some of this can be done with the WLM policy in hand. But this is about an SMF-based approach. (The piece you can't do with SMF is discerning the WLM classification... [More]
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Tivoli Workload Scheduler and Workload Manager Service Classes
I don't think I've mentioned this before in this blog but Tivoli Workload Scheduler (TWS) has a nice "WLM Integration" feature. With it TWS can change the Service Class a job runs in - before submission. The main purpose of this is to elevate Critical Path work. We wrote about this in the Redbook mentioned in Touring The Upcoming Batch Optimization On z/OS Redbook , and so some of... [More]
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zAAP and zIIP Delay
I was going to start this post with an apology. But, as any sensible blogger would, I left it a few days to write this. Now I realise that there's a wider point than the "I was wrong" one. (But I was wrong - in a way that I think many other people might've been wrong too.) So let me talk about two things in this post: zAAP and zIIP Delay. How I came to be wrong and what we can all... [More]
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DDF Performance - Version 3 - but still highly relevant
I've just submitted a set of slides to Slideshare. They're not mine, they're not new, they're not even in a modern format. But they are a very good presentation worth preserving... In 1993 Curt Cotner presented a set of slides on the new DDF Inactive Thread support in Version 3 of DB2. It's still highly relevant and this support was the base on which the Version 4 WLM classification line item was... [More]
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