Thanks Scott. I guess you could say that it may need consideration when trying to push your existing h/w to the limit, much like how WLM is to ration resources out when things are running tight.
– Vignesh Mainframe Infrastructure -----Original Message----- From: IBM Mainframe Discussion List <[email protected]> On Behalf Of Scott Chapman Sent: 09 November 2018 12:51 To: [email protected] Subject: [EXTERNAL] Re: I/O priority Interesting you should mention that. Most systems we see do in fact have I/O priority management enabled. (Groups less so.) However, that will affect the computed velocity. And in some cases it can skew the velocity in ways that may be counter-productive. And the problems that I/O priority management solves are generally much less of a problem today than in the past. A long-standing recommendation has been to enable I/O priority management, but I'm now researching whether or not that recommendation is still the correct one. I'm leaning that is not (i.e. I/O priority management may be better left disabled), but I've been busy the past several weeks and haven't finished all the research I want to do. So the short answer for now is that if you don't have it enabled, I wouldn't enable it today. If you have it enabled, I can't really say if it's problematic for you without looking at your data. If you do enable (or disable) I/O priority management you will need to re-evaluate your velocity goals. In most, but probably not all cases, I suspect the issues are relatively minor either way. In at least a few specific cases, having I/O priority management enabled may be leading to WLM not being able to effectively manage certain service classes. Note again: this is something I'm still researching and I hope/expect to present on the topic at the next SHARE. Scott Chapman Enterprise Performance Strategies On Fri, 9 Nov 2018 04:52:01 +0000, Sankaranarayanan, Vignesh <[email protected]> wrote: >Hello everyone, > >Has anyone here had any experience with enabling I/O priority >groups/management in WLM.. ? >I understand it has to be enabled in all systems connected to the DASD... what >are the gotchas or things to watch out for. > ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN MARKSANDSPENCER.COM ________________________________ Unless otherwise stated above: Marks and Spencer plc Registered Office: Waterside House 35 North Wharf Road London W2 1NW Registered No. 214436 in England and Wales. Telephone (020) 7935 4422 Facsimile (020) 7487 2670 www.marksandspencer.com Please note that electronic mail may be monitored. This e-mail is confidential. If you received it by mistake, please let us know and then delete it from your system; you should not copy, disclose, or distribute its contents to anyone nor act in reliance on this e-mail, as this is prohibited and may be unlawful. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
