This article describes the Exchange Online Auto-Expanding Archiving feature.
The Exchange Online Archiving feature is available to all Exchange Online users at Virginia Tech. It is a mailbox that exists in the cloud and is intended to be an Exchange Online mail archive. It appears alongside your primary mailbox folders in Outlook or Outlook on the web. Its name is “In-Place Archive – Last name, First name” in the Outlook Web App and “Online Archive – Last name, First name” in Outlook.
This archive mailbox represents an additional storage allocation of 1.5 TB along with the primary mailbox’s own 100 GB. Users can access, store, and search for items the same way as their other mailboxes.
To set an archive policy for a folder in Exchange Online that will be used by this feature
To set an archive policy for a folder in Outlook that will be used by this feature
Auto-expanding archiving is the facet of this feature that provides auto-expanding archive space in the cloud in 100 GB chunks up to 1.5 TB. Each time a user’s Exchange Online archive mailbox uses the 100 GB allocation, it is expanded by an additional 100 GB.
From Microsoft's Overview of this feature:
"Auto-expanding archive is only supported for mailboxes used for individual users (or shared mailboxes) with a growth rate that doesn't exceed 1 GB per day. A user's archive mailbox is intended for just that user. Using journaling, transport rules, or auto-forwarding rules to copy messages to an archive mailbox is not permitted. Microsoft reserves the right to deny unlimited archiving in instances where a user's archive mailbox is used to store archive data for other users or in other cases of the inappropriate use."