The current default schedule, set in backups.conf and journals.conf, is to backup and purge journals daily, and to keep 3 backup files and 3 journal files.
These are not good defaults, because a production database will typically go through more than one journal file in a day, and the journal files should extend back as far as the oldest backup.
Another problem is that journal files are typically being rolled at their maximum size of 4 GB, which is awkwardly large, e.g. for moving or extracting. And since the journals roll due to size, they roll depending on database activity rather than a timed schedule, so predicting how many files need to be kept for the associated daily backups is unreliable.
A much better configuration is to set a cron job to roll the journals hourly, which rolls them long before they reach 4 GB. This ensures 24 journal files per day plus an additional file rolled at the time of the backup. Then num_journals can be reliably set by multiplying the number of daily backups by 25. Another advantage of the hourly rolling is that the journals are then divided in a clear chronology, so for example, to see what happened at a particular time you can just extract the journal file for that hour, and you can see how journal growth varies by the time of day.
To implement this by default, an hourly cron job for ovswitchjournals needs to be added to /etc/cron.d/openvista by ovinstanceadd, and num_journals needs to be set to 75 in /usr/share/openvista/journals.conf.
Odds and ends that may be useful...
Rolling the journals hourly guarantees at least 24 journal files a day, but it could be more if in one hour the application generates enough data to roll the journal file.
You can set a maximum journal file size of less than 4GB, if 4GB journal files are too unwieldy.
When a journal file is rolled, the former journal file is renamed with a timestamp.