Sun Java System Calendar Server 6.3 Administration Guide Using Read-only Mode

If you are encountering database corruption, one way to prevent service interruptions is to put your database in read-only mode. This mode allows end users to read database entries, but does not allow additions, modifications, or deletions. If an end user attempts to add, modify or delete any calendar data, the system gives an error message. In addition, administrator tools that add, modify or delete calendar events and todos will not work while the database is in read-only mode.

Note –

If the database is corrupted to the point that it can’t be read, you must interrupt service long enough to restore a backup. The quickest way to restore a backup is to have a good hot backup. See Before You Restore.