Filtered remote journals
Remote journal filtering allows for the journal receiver on the target system to not be a complete copy of the journal receiver on the source system. Filtering allows some number of journal entries to not be sent to the target system. Not sending all journal entries decreases the amount of data on the communication line. Care must be taken when defining remote journal filtering to ensure that critical data is not filtered.
Remote journal filtering is available under Option 42 of the IBM® i Operating System, feature 5117 (HA Journal Performance). Three criteria can be used to filter entries sent to the remote system; before images, individual objects, and the name of the program that deposited the journal entry on the source system. The filtering criteria are specified when activating a remote journal. Different remote journals associated with the same local journal can have different filter criteria. Remote journal filtering can only be specified for asynchronous remote journal connections. Note: Since journal entries might be missing, filtered remote journal receivers cannot be used with the Remove Journaled Changes (RMVJRNCHG) command. Similarly, journal receivers that filtered journal entries by object or by program cannot be used with the Apply Journaled Change (APYJRNCHG) command or the Apply Journaled Change Extend (APYJRNCHGX) command.
Often, before images are captured on the source system to allow for debugging, or for commitment control purposes. Sometimes these entries are not required on the target system. All before images can easily be filtered from a remote journal.
In some environments, non-critical files are journaled on the source system because of commitment control requirements. The journal entries for these non-critical objects can be filtered out in a remote journal environment and not sent to the target system if they are not needed there. Each object that is to have journal entries filtered must be changed to contain the remote journal filter indication. The Change Journaled Object (CHGJRNOBJ) command can be used to set this remote journal filter indication. Objects that automatically start journaling due to library journaling can have the indication set when they start journaling based on the inherit rules defined for library journaling.
Occasionally, journal entries deposited on behalf of a given program are not needed on the target system. These journal entries can be omitted with remote journal program filtering. This filtering can only be specified by using the QjoChangeJournalState API.
See these commands and API for details on remote journal filtering: