Allied Telesis AT-S63 - Manual (Page 210)

Chapter 12: Event Log
210 Section II: Advanced Features
4. To determine what action the switch takes when the event log
reaches its maximum capacity, type 2 to toggle Log Full Action
between the two selections:
Wrap
When the event log reaches its maximum capacity, this option
deletes old entries and continues to add new entries. This is the
default.
Halt
When the log file reaches its maximum capacity, the log stops
adding new entries.
5. After making changes, type R until you return to the Main Menu. Then
type S to select Save Configuration Changes.
To display the events in the log, go to the next procedure.