CF LPARs In The GCP Pool?

This post is about whether to run coupling facility (CF) LPARs using general purpose processors (GCPs). It might be in the category of “you can but do you think you should?” I’d like to tackle this from three angles: And the reason I’m writing about this now is the usual one: Recent customer experiences andContinue reading “CF LPARs In The GCP Pool?”

Mainframe Performance Topics Podcast Episode 32 “Scott Free”

Episode 32 was, as always a slow train coming. I think it’s a fun one – as well as being informative. It was really good to have Scott back, and we recorded in the Poughkeepsie studio, just after SHARE Atlanta, March 2023. Talking of which, the aftershow relates to SHARE. It’s a classic example ofContinue reading “Mainframe Performance Topics Podcast Episode 32 “Scott Free””

When Good Service Definitions Turn Bad

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”

Heading Back Into Db2- Architecture Part 1

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”

Coupling Facility Structure Versions

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”

Mainframe Performance Topics Podcast Episode 31 “Take It To The Macs”

This is the first blog post I’ve written on my new work MacBook Pro. While it’s been a lot of work moving over it’s a better place as it’s an Apple Silicon M1 Max machine with lots of memory and disk space. That’s nice, but what’s the relevance to podcasting? Well, it’s very warm hereContinue reading “Mainframe Performance Topics Podcast Episode 31 “Take It To The Macs””

WLM-Managed Initiators And zIIP

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”