A method and apparatus which provide solutions for avoiding journal
overflow in after and before journal methods of a backup and recovery
system used with a storage system. The after journal method solutions,
which are conducted when the amount of free space reaches a threshold,
include periodically taking a new snapshot and deleting the oldest
journal, periodically taking a new logical snapshot and deleting the
oldest journal, stopping the taking journal entries when the journal
volume is full, and stopping the taking journal entries when the journal
volume is full and then switching to bitmap management. The before
journal method solution, which is conducted when the amount of free space
reaches a threshold, includes applying wrap-around overwriting to
overwrite the oldest journal entry by the newest journal entry.