Why Shared Mailboxes in Office 365 Are Not Backup
Microsoft ensures that Office 365 is highly available, and the service has been designed to be highly redundant, What Microsoft don’t do is protect against malware, accidental deletion or handling leavers/movers accounts. Ensuring your data (Which Microsoft state is your responsibility) is secure should be a priority.
One practice we have come across to achieve this is Admin’s using Shared mailboxes as a ‘backup’ for a user’s mailbox. There are a couple of ways this can be implemented.
- Admins create a Shared Mailbox named
Username.SME@acme.com. Then, they setup an auto-forwarding rule on the
employee’s primary mailbox, which automatically sends a copy of all emails to
the Shared Mailbox, creating a secondary copy.
- The second occurs when an employee leaves or is terminated. In this scenario admins deactivate the license and convert the user’s mailbox to a Shared Mailbox for long-term retention.
While both seem like a good idea there are some limitations you should consider:
- The restoration process is complicated, potentially requiring a user or admin to sift through hundreds if not thousands of messages in the Shared Mailbox.
- Storing emails in Shared Mailboxes does not give you an independent second copy of emails
- If you want to enable In-Place Archive, In-Place Hold, or Litigation Hold on a Shared Mailbox, an Exchange Online Plan 2 or an Exchange Online Plan 1 with Exchange Online Archiving license is required.
- Shared Mailboxes have a 50 GB data limit unlike User Mailboxes which can store up to 100 GB. Therefore, you could easily exceed your quota for the Shared Mailbox.
- Any organizational hierarchy within a mailbox (ie: folder & subfolder structure) is lost when performing a restore.
- Shared Mailboxes are still subject to accidental deletion by administrators. It’s a smaller risk but still a possibility.
Whilst the above might seem like an ‘easy’ way to achieve a backup of your Exchange it doesn’t compare to the capability of a full Office 365 Backup service that can protect Exchange, SharePoint and OneDrive for business Which are fully designed to enable you to easily restore either a full account or individual items quickly and easily.
For more information on UK Backup’s Office 365 Backup service click here.