Episode 17 "Two Good, Four Better"

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.