Scott, I am the OP.
I definitely appreciate your comments (and everyone else's too), but no one was commented on the other half of my questions. At what point or percentage (records written/space used) would it be advisable to split out 92s, 99s, 120s into their own logstreams? Right now they are all in Default. A coworker tested turning on 120s in WebSphere for an hour and then grew it into an estimated 2 million records that would use 48% of the space after 8 hours. Not sure if that was one WAS server or more, but that certainly got his attention. I realize YMMV, but am canvassing for real world experiences here. Bob -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Scott Chapman Sent: Friday, February 09, 2018 7:31 AM To: [email protected] Subject: Re: SMF advice on additional logstreams Remember when looking at SMF volume, record counts are interesting, but the bigger issue is the number of bytes written. We (Peter Enrico and myself) recommend collecting at least 99 subtypes 6, 10, 11, 12, and 14. 6 is especially important as it's the summary service class period information (every 10 seconds) 10 is dynamic processor speed changes, which you hopefully don't see 11 is for Group Capacity limits, and is written every 5 minutes 12 is HiperDispatch interval (2 second) data which can show you utilization information on a 2 second basis which can be quite interesting 14 is HiperDispatch topology data written every 5 minutes or when a change occurs The 6s and 12s are in fact high volume in terms of the number of records, but the records themselves are relatively short. In terms of bytes, from what I've seen the subtype 6 is somewhere between 40 and 100 MB of additional SMF data per system per day. Subtype 12 seems to run around 40 to 50MB. I expect that's not noticeable in most environments. Indeed, the type 30s can easily be more data than that. Not to mention the 101s, 110s, and 120s. I actually have a slide on this in an upcoming conference presentation. The other 99 subtypes are used less often and some can be more voluminous than the 6 summary records. If you don't want to record those subtypes all the time, I'm ok with that. But OTOH, if you need them to do a deep dive on WLM to try to understand why things worked the way they did, then having them handy is better than having to turn them on and recreate the issue. We don't formally recommend people keep them enabled, but if it was me, I'd probably keep at least most of them enabled. The 92s are file system information. The subtypes 10 and 11 are written every time a file is opened/closed. In large Websphere Application Server environments I've seen these being very voluminous. I haven't looked at them lately, but my recollection from quite some time ago is that directory traversal (at least in the HFS file systems) triggered these records as well. I've seen the 92s in such an environment being much more voluminous than the 99s. In that environment, I did have the 92s turned off because of this. There are relatively new subtypes (at least 50-59) in the 92s, that may be why the OP is seeing more 92s. It looks like possibly useful information if you're tuning zFS performance, but I personally haven't spent any time yet investigating them. Scott Chapman On Thu, 8 Feb 2018 16:17:47 +0000, Allan Staller <[email protected]> wrote: >Not sure about SMF92, but SMF99 are "WLM decision records". > >Yes they are large volume, but somewhat indispensable. > >Generally when there is a WLM problem it is extremely difficult or impossible >to reproduce. >If the SMF99's are not available "during the problem" it is virtually >impossible to debug. > >IMO, SMF99's should be recorded. I know Cheryl Watson and others may disagree. > >My US$ $0.02 worth, ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
