Radoslaw, Isn't this also the case for VSAM when you lose your OS with the files open?
I may be out of date or have a lapse in memory, but I recall a file journaling option that allowed CICS to roll forward/back updates to a file with LSR buffered writes. It could be just another senior moment. Ron -----Original Message----- From: IBM Mainframe Discussion List <[email protected]> On Behalf Of Radoslaw Skorupka Sent: Friday, 8 October 2021 4:36 AM To: [email protected] Subject: Re: [IBM-MAIN] CICS VSAM LSR pools and IBM DASD PPRC type mirroring. W dniu 23.09.2021 o 22:21, Ward, Mike S pisze: > Hello, all. I don't know if any of you are doing disk replication to a DR > site, but we are, and we are trying to resolve a specific problem with CICS > and VSAM file. > > CICS, in the case of LSR pools hold the data in the buffers until a buffer > shortage\wait type of condition occurs. When that happens CICS flushes the > buffers and updates the high used RBA's of the files. In the case of a DR > test. We use the data as is. We copy the current replicating data to other > DASD so that we can perform the test by bringing up the system and testing > it. Well the only way we can think of making sure we get all the VSAM data is > by closing the files at the production site which is not feasible. Is anyone > else doing this kind of mirroring, and are there things you are doing that > fixe the VSAM buffering problem? The only thing I can think of doing is > adjusting the LSR buffer pools so that waits occur every so many minutes, I'm > staying away from share option 4,4 on the VSAM files which are a real > performance hit. Any takers are welcome. Also as an aside the implication > here is that in the case of a real disaster there is data missing from the > VSAM files, or am I wrong and full of it? Any help, opinions, whatever are > welcome. General rule: PPRC and other methods is for "wise" applications. That mean the application/system must survive sudden blackout with no harm to data consistency. Otherwise remote copy is fuzzy. Yes, both asynchronous and synchronous remote copy are for disaster recovery. What does it mean? Fire, bomb, flood, power outage, whatever else. In any case the applications on the remote site is more or less like someone switched off power in the server during... of course, we don't know when and we cannot demand prerequisite actions. It is sudden, unexpected. The only difference between power outage and DR is the application is restarted on another machine. Conclusion: your system elements have to be "wise" or DR aware. This is called transactional system. Not because it processes business transactions, but it processes transactions as Logical Unit of Works. Yes, you can loose not finished transaction, but this is all-or-nothing. Transaction is committed or not. Whole one. How does it relate to CICS and LSR? Similarly to DB2 and bufferpools. Bufferpools are good, but committed transaction has to be written on DASD, in the transaction log. BTW: SHR(4,4) is good in z/VSE, not in z/OS. -- Radoslaw Skorupka Lodz, Poland ---------------------------------------------------------------------- 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
