There are no traditional methods of backup in Exchange Online. In other words, you cannot backup your mailboxes to disk or tape to restore in the event of a failure. This means one of two things:
- You place your trust in Microsoft to never lose your data.
- You find another method.
Clients I work with like to use Retention Policies. Placing mailboxes on hold can retain email. If an email is deleted it is moved to the recoverable items folder and it stays there. It is retained depending on the configuration of policies in play.
This is great, until the recoverable items folder reaches maximum size.
When a mailbox is placed on hold or has an archive enabled, the recoverable items folder size is increased from the default of 30GB to 100GB. Now this may sound like a lot. However, we all have users who receive too much email and even if they delete it all, it is retained. Over a period of years, this may eventually reach the current limits on the user mailbox. After that, you will want to use the user’s archive to store recoverable items. To do this, you will need to enable the auto-expanding archive feature. You will also need to apply an Exchange retention policy that moves items from recoverable items folder in the user mailbox to the archive. The link below will help you achieve this.
