That was my thinking too Paul. We should be able to mask a lot of this in software and not have to do a lot of unnecessary “busy” work.
Part of the challenge is to identify some behaviors that could be deprecated. We have a lot of baggage in the z/OS wagon. The defrag comment got me to thinking about possibilities that we at Ibm might start to consider Matt Hogstrom +1 (919) 656-0564 > On Jan 12, 2020, at 15:49, Paul Gilmartin > <[email protected]> wrote: > > On Sun, 12 Jan 2020 13:59:21 -0500, Matt Hogstrom wrote: > >> Out of curiosity, its been a while since I did storage admin but it occurred >> to me that for the most part a lot of the work in defragging, worrying about >> disk geometry and other issues are really not / less of an issue with cache >> and SSD technologies. So, perhaps naive on my part, but it would seem to me >> the work to “defrag” is really more to keep up the legacy z/OS concepts like >> # of extents, CKD processing for PDS’, etc. Are there benefits to >> defragging these days apart from the consequences of the limitations from >> older architectures and paradigms like directory blocks and member placement? >> > Alas, while the new technologies bypass the performance impact of > fragmentation, insofar as they faithfully emulate older hardware it's > still possible to have virtual space exhaustion. Aren't PDSes still > limited to 65,535 virtual tracks? PDSEs are better at reclaiming space. > > I could imagine a Super-IEBCOPY's updating directory blocks and > DS1LSTAR and reclaiming space so virtually freed. Only imagine. > > Even as SSD firmware moves and remaps physical blocks to > counteract fatigue. > >> -----Original Message----- >> On Sun, 12 Jan 2020 09:32:01 -0800, Charles Mills wrote: >> >> When you compress a PDS aren't you essentially de-fragging it? No, not the >> way the word is used on PC disks, but you are essentially consolidating >> fragments of free space into one big chunk of free space. >> >> -----Original Message----- >> From: Jeremy Nicoll >> Sent: Sunday, January 12, 2020 1:28 AM >> >> I dunno about the first bit, but "routine mainframe defrag" is fine. >> DFDSS has a DEFRAG verb. >> > I used to believe that DB2 might require a REPRO to reclaim orphaned > CA/CIs. Is that still the case? > > -- gil > > ---------------------------------------------------------------------- > 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
