Hello Doug,
Am 13.02.2026 um 16:51 schrieb DEnglander--- via MIDRANGE-L <midrange-l@xxxxxxxxxxxxxxxxxx>:
Does anyone know of any resources or Best Practice guidelines regarding how long to keep journal objects on the disk? We have journals that are taking up quite alot of disk space, and I am wondering how long they normally need to be kept online. At least weekly there are messages in QSYSOPR indicating a journal has been detached and should be saved. However, once the journal is saved to tape, how long is it necessary to keep it on disk?
Nobody can answer that question better than you. Let me give you some hints to think over.
What are journals good for? To my understanding:
- Intermediate storage for transactional processing
- Log of changes to tables (PFs)
- Log of changes to access paths (LFs)
Journals are used by the system in case of a crash due to power outages, etc. to speed up recovery. Since journal receiver contents are frequently saved to disk, recovery is usually possible with only the latest receiver(s) on disk, and older ones (usually having been moved to tape) not needed.
Journals also can manually be used to reset fatal changes to a table, such as an SQL UPDATE or DELETE with a missing WHERE. Caveat: To reset changes to an arbitrary point in time, both before and after images need to be written to the journal receiver, and the receiver with the fatal change must be on disk, with the whole chain to "now", which might require a restore from backup.
If you don't use images(*both) but the default *after, and want to reset a change, you need the whole chain of receivers from the very beginning of when a table was last journaled (strjrnpf). If you have already overwritten older tapes, you can't undo the change.
Note: This is to my understanding. I have not yet taken time to play around with the possibility to reset fatal changes, but it's on my list of things to learn about.
There might be further use cases, such as audit trails vs. auditors. Maybe others can elaborate on the practical implications in the U.S. I'm just a hobbyist with much more relaxed requirements.
Concluding, IMHO, you're safe to let the system handle journal receivers, including their automatic deletion after they have been saved.
If you want the extra safety net of being able to "reset" catastrophic changes, the main question is: How long might such an event go unnoticed? I assume, the one who did it will immediately go very pale seek support, so the receiver currently in use has recorded the fatal change, and is available on disk.
As always: Your mileage may vary.
:wq! PoC
midrange.com
