The rule of thumb for the appropriate number of log switches is one every 15 minutes, that is, 4 per hour.

The archive log destination contains archive logs - database journal entries (changes to the database). As changes are recorded in the database, change vectors are written to the log buffer. The log buffer is regularly flushed and its entries are written to one of at least two online log files.

When these online log files fill up two things happen:

1. A log switch is performed whereby change vectors writes are switched to a new online log file
2. The old online log file is archived (copied) to an archive log destination.