Something realized while working a a client was that we typically configure a G-F-S (Grandfather-Father-Son) backup retention with backups been retained by month going back for the prior year. So typically at best our granularity for recovery is a 30-ish day window. However, the default configuration in Exchange is to provide a 14-day retention for deleted items. A quick check here shows that there is a window where data can be received and deleted without ever being written to a recoverable backup.
· Exchange retention periods should exceed the longest period between retained backup media (typically around 30 days; but some rotations use true month end, others last Friday of the month, etc., so this date should be adjusted upwards)
· Making sure the customer is aware that we have a retention based system and it is not a true e-mail archiving system, which can add to backup costs substantially.