Exactly. Let the channels emulate CKD and have maps to the actual data. NVME even got rid of the hard disk emulation layer.
On Sun, Jan 12, 2020 at 6:41 PM Matt Hogstrom <[email protected]> wrote: > > 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 -- Mike A Schwab, Springfield IL USA Where do Forest Rangers go to get away from it all? ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
