Tag Archives: performance

They say beauty is in the eye of the beholder. But I hope you’ll agree this is a pretty interesting graph. It is, in fact, highly evolved – but that evolution is a story for another time and place. I want to talk about what it’s showing me – in the hope your performance kitbagContinue reading “A Very Interesting Graph”

I was about to comment it’s been a while since I wrote about WLM but, in researching for this post, I discover it isn’t. The last post was WLM-Managed Initiators And zIIP. I seem to be telling a lot of customers their WLM service definition really needs some maintenance. In fact it’s every customer I’veContinue reading “When Good Service Definitions Turn Bad”

I loftily talk about “architecture” a lot. What I’m really getting at is gleaning an understanding of an installation’s components – hardware and software – and some appreciation of what they’re for, as well as how they behave. When I started doing Performance and Capacity – many years ago – I was less sensitive toContinue reading “Heading Back Into Db2- Architecture Part 1”

When I see an 8-byte field in a record I think of three possibilities, but I’m prepared to discover the field in question is none of them. The three prime possibilities are: A character field A 64-bit counter A STCK value An interesting case occurs in SMF 74 Subtype 4: Two similar fields – R744SVERContinue reading “Coupling Facility Structure Versions”

One item in the z/OS 2.5 announcement caught my eye. Now 2.5 is becoming more prevalent it’s worth talking about it. It is zIIP and WLM-Managed Initiators. WLM-Managed Initiators The purpose of WLM-Managed Initiators is to balance system conditions against batch job initiation needs: Start too many initiators and you can cause CPU thrashing. StartContinue reading “WLM-Managed Initiators And zIIP”

I’ve written several times about System Recovery Boost (SRB) so I’ll try to make this one a quick one. For reference, previous posts were: Really Starting Something SRB And SMF Third Time’s The Charm For SRB – Or Is it? From that last one’s title it clearly wasn’t (the end of the matter). It’s worthContinue reading “SRB And Shutdown”

For quite a while now I’ve been able to do useful CPU analysis down at the individual logical processor level. In fact this post follows on from Engineering – Part Five – z14 IOPs – at a discreet distance. I can’t believe I haven’t written about Defined Capacity Capping before – but apparently I haven’t.Continue reading “Engineering – Part Six – Defined Capacity Capping Considered Harmful?”

Passing reference to Blondes Have More Fun – Or Do They?. Yeah, I know, it’s a tortuous link. 🙂 And, nah, I never did own that album. 🙂 I first wrote about System Recovery Boost (SRB) and Recovery Process Boost (RPB) in SRB And SMF. Let me quote one passage from it: It should alsoContinue reading “Third Time’s The Charm For SRB – Or Is it?”