7. The method according to claim 1 , wherein the event is editing document data as a target.
7. The method according to claim 1 , wherein the event is editing document data as a target. 9. The method according to claim 7 , further comprising in a case where a medium for backup on which replicated document data is stored is removed from a drive, a replication source of the replicated document data is edited and the medium is mounted again on the drive, updating the replicated document data depending on editing details of the replication source.