DSNTYPE=LARGE allows the 65,535 track (4,369 cylinder) limit to be exceeded. This should be restricted to SPOOL datasets and the like.
DSNTYPE=EXTENDED does NOT allow this size limit to be exceeded. -----Original Message----- From: IBM Mainframe Discussion List <[email protected]> On Behalf Of Paul Feller Sent: Wednesday, February 21, 2024 4:10 PM To: [email protected] Subject: Re: Something keeps releasing space on a large (annual) DS CAUTION: This email originated from outside of the Texas Comptroller's email system. DO NOT click links or open attachments unless you expect them from the sender and know the content is safe. Bob, sorry we should have answered some of your questions at the end of your email Let me start by saying your storage management team should be able to answer all your questions. That said I'll answer some of your questions based on what I know. These are general answers. The SMS environment you are running under could have overrides that may affect what happens. You asked "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?" Basically, an extended format dataset is allowed to be bigger than a standard (or none extended) in several ways. Extended format allows for 123 volumes where non-extended is 16 volumes. Extended format allows for far larger allocation of a dataset on one volume then a non-extended. If I recall a non-extended max size is 65,535 tracks. As far as I know using 3.2 to allocate the data should not be an issue. It should (as far as I know) drive the same SMS ACS routines that are used in batch. Paul -----Original Message----- From: IBM Mainframe Discussion List <[email protected]> On Behalf Of Bob Bridges Sent: Wednesday, February 21, 2024 11:45 AM To: [email protected] Subject: Something keeps releasing space on a large (annual) DS 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 ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
