Try VTOC backups after Recall 3 and update 5 and restore 7 and compare. On Mon, Mar 6, 2023 at 11:08 AM Dave Jousma <000001a0403c5dc1-dmarc-requ...@listserv.ua.edu> wrote: > > All, > > We just learned that we have a problem with IAM (Innovation Access Method) > the high perf replacement for VSAM. No idea how long it has been going on, > and I have tickets open with both BMC and IBM on this. Seems to only affect > IAM files, and exists in both z/OS V2.4, and V2.5, and multiple versions of > IAM. We are currently at 10.x, but the problem occurs in V9.x as well. We > see the problem mostly in our Development space, not in PROD (or nothing > reported yet, but problem exists there too). We dont migrate much in PROD, > and is why we havent had the problem reported there. > > The scenario here is > - existing IAM file gets updates, records added or updated, doesnt matter. > - file goes unreferenced for 7 days, so HSM migrates > - file gets recalled, the updates that were made are gone. > > In HSM we do have FSM enabled (Fast Subsequent Migration), where if HSM is > called to migrate the dataset, and it hasnt changed since last migration, it > just deletes the dataset and reconnects it to the already migrated version in > HSM. > > We've learned that turning FSM off circumvents the problem. IBM tells us > that "HSM checks the DS1RECAL and DS1IND08 flags in the Format-1 DSCB of a > data set to determine if a data set is eligible for fast subsequent > migration. The DS1RECAL flag is used to indicate if a data set has been > recalled and the DS1IND08 flag is used to indicate if a data set been > modified since it was last recalled. " > > IBM doc seems to indicate that OPEN handles setting these bits, BMC support > says they arent messing with these bits. I dont know *who* is to blame. > > I'd be curious to hear from other installations that use IAM, has HSM with > FSM turned on. > > The recreate scenario is (assumes new test file) with FSM turned on > 1 - Allocate test IAM file and add a record easily identifiable > 2 - HSM Migrate the file > 3 - HSM Recall the file > 4 - RECORD ADDED IN #1 is there. > 5 - Add another record with new identifiable info > 6 - HSM migrate the file. > 7 - HSM Restore the file. > 8 - Record from #1 is there, record from #4 is not there. > > With FSM turned off, the dataset gets fresh migration copy every time, so the > issue is masked. > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@listserv.ua.edu 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 lists...@listserv.ua.edu with the message: INFO IBM-MAIN
