PS-E (extended format) allows for 123 extents on a single volume. If the allocated dataset is SMS managed its assigned management class is likely the reason why free space is being released.
Mark Jacobs Sent from ProtonMail, Swiss-based encrypted email. GPG Public Key - https://api.protonmail.ch/pks/lookup?op=get&[email protected] On Wednesday, February 21st, 2024 at 12:44 PM, Bob Bridges <[email protected]> wrote: > I'm not a sysprog (just a security geek), but I can at least allocate > datasets, and at the start of this year it fell to me to allocate a new > dataset in which are logged all changes made in the security system. Past > year's log are in the 12000-track range, so I started with a smaller > allocation while I took the time to talk to our sysprog about space > requirements. It's populated from a daily production job, by the way. > > When I re-allocated it, on his advice I tried a multi-volume and extended > allocation (PS-E). Almost immediately the job started bombing, claiming that > the first four volumes it tried didn't have the necessary space to add an > extension. The sysprog is puzzled - says it should have looked in volumes > that DO have the space, not the ones that don't. > > Second attempt (I don't count the temporary smaller allocation) I kept PS-E > but dropped the multi-volume requirement. I've never done one of those > anyway, and don't trust 'em. The system promptly dropped the extra tracks I > allocated, and a day or two later the job started bombing with a B37-04. > > Third attempt: Forget PS-E (I'm unfamiliar with that too) and just used > SPACE=(TRK,(9000,1000)). That seemed to work for a whole week, but I just > noticed that something, somewhere, has released extra space AGAIN; 3.4 tells > me it's now 1960 tracks and 83%. The job isn’t bombing yet; some time later > in the year I'm guessing it's going to. > > Pardon my frustration: WHAT THE HECK IS GOING ON? Why does it keep releasing > space although I never specified RLSE? The sysprog doesn't know either - but > he's an external contractor who just took over the system a few months ago > and if it's something simple he may not be aware yet of ... I dunno, > something in SMS maybe? > > Some wrinkles that may or may not be relevant: > > 1) The dataset is written using a REXX exec that calculates the DSN by > reference to the current year. This relieves folks from having to update the > JCL every year, but maybe something about the way the exec does the allocate > is causing the problem? I'm guessing not, because as far as I now this job > has run correctly for years. But just in case: > > "ALLOC DDN(CHG$$OT) DSN('<dsn>') MOD CATALOG REUSE", > > "SPACE(300,30) CYLINDERS RECFM(V,B) LRECL(304) BLKSIZE(27998)" > > 2) I don't know anything about SMS, but could something there be releasing > space? > > 3) What IS extended PS, anyway? I'm told it allows more than 16 extents, but > a) how many more? And b) how else is it different? > > 4) I allocated the dataset each time using not batch JCL but 3.2 ... > expecting there's no difference. > > --- > Bob Bridges, [email protected], cell 336 382-7313 > > /* Law #6 of combat operations: If it's stupid but it works, it isn't stupid. > */ > > ---------------------------------------------------------------------- > 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
