Hi,
We wish to use Exchange Online Archiving to keep a full archive of all of our mail. We have on-premises Exchange 2013 and will configure a hybrid deployment with Office 365. The archive mailbox for each user will be in Office 365 (via EOA licenses).
Every user will have Litigation Hold enabled.
My understanding is that when a user is deleted from our on-premises environment, EOA will keep the archive forever without consuming a license (via the Inactive Users feature) due to the fact that Litigation Hold was enabled at the time the user was deleted.
Mail will be moved to the archive by a default retention policy assigned to all users which will be something like "move all mail older than 6 months to the archive".
The last hurdle which I am unsure about is what happens when a user leaves our company and their AD account is deleted. At this point, the on-premises Exchange 2013 mailbox will be deleted but the online archive will remain. The email in their on-premises mailbox will be lost (as it was never moved to the archive) which will be the last 6 months worth of email.
Is there a good way to deal with this issue? I realise we could put a process in place (eg, when a user leaves someone manually moves all of their email to the archive) - but the goal here is to be confident that all email is kept, no matter what. I don't want it to be a case of "all email will be kept AS LONG AS person X followed the right process". That doesn't seem like proper archiving to me.
What do other people do? Is there a good solution?
Cheers,
David