Preventing a full journal (undamaged CDS)

To help prevent the problem of a full journal, ensure that your journal is of adequate size to record all the activity between backups of the CDSs. In conjunction with that, schedule CDS backups frequently enough so that the journal can handle the activity. Most installations run automatic backup once a day, seven days a week; the journal data set therefore needs to be large enough to contain data for a 24-hour time period.

Consider using a large format data set for the DFSMShsm journal. A large format data set is a physical sequential data set with the ability to grow beyond 65,535 tracks per volume. Using a larger journal data set can allow more DFSMShsm activity to take place between journal backups and helps to avoid journal full conditions.

Also, use the SETSYS MONITOR (JOURNAL) command to send your warnings when the journal data set is getting full. When the journal data set is filled to the specified threshold, which you can set to any percentage from 0 to 100 or leave at the DFSMShsm default value of 80%, a warning message is issued to the system operator. Messages continue to be issued until the journal data set is 100% full. Set your threshold at a value that gives you adequate time to back up your CDSs and journal and to allocate a new journal.

Customers that have NetView® or another automation product can monitor the ARC0909E and ARC0026E messages, keying in on the 100% and EOV message variables. When 100% and EOV are issued, NetView can automatically issue the BACKVOL CDS command.