Redundancy = Reduce the number of component failures that can lead to system failure (RAID, live replication, hot standby).
Backup = Recover from an obvious failure or overwite (Weekly full backups, daily differentials).
Archival = Recover from a non-obvious failure and/or malicious activity (WORM tapes, offsite backup).
As a failsafe against malicious sysadmins is to split up the responsibilities. The guy handling backups isn't handling archival etc...
Redundancy = Reduce the number of component failures that can lead to system failure (RAID, live replication, hot standby).
Backup = Recover from an obvious failure or overwite (Weekly full backups, daily differentials).
Archival = Recover from a non-obvious failure and/or malicious activity (WORM tapes, offsite backup).
As a failsafe against malicious sysadmins is to split up the responsibilities. The guy handling backups isn't handling archival etc...