Deployment of Exchange Online Expandable Archives Paused

Exchange Online expandable archives

Exchange Online and its Ever-Expanding Archives

In a surprise announcement in the Office 365 Message Center, Microsoft revealed on December 1 that they had paused the deployment of the “bottomless” archive mailboxes within Exchange Online.



The most interesting words in the announcement was the reason given. The pause is “to ensure the most stable environment for our customers”. In other words, some problems have been found with how the expandable archives work.

When I previously covered this topic on October 18, I noted that the deployment was complete in the Australia and APAC Office 365 datacenter regions. At that point, Microsoft anticipated being able to continue the deployment to the larger regions (EMEA and the U.S.) in the coming months, subject to no problems being found.

It’s hard to know where the problems that provoked the pause might lie. The idea of combining 50 GB chunks into a logical mailbox structure is both simple and complex at the same time. It’s easy to see how the mechanism might work well in the lab and then run into complications when exposed to the 100,000-server Exchange Online environment where mailboxes from multiple tenants are stored in databases.

Fools Rush in Where Programmers Pause

All in all, it’s good that Microsoft has paused to review how expandable archives work in practice and make whatever changes are necessary to allow the deployment to proceed. I understand that the largest expandable archive currently in production is well over the 1 TB mark. The technology obviously works, even if it has hit a bump.

Although archives are intended to store information that is accessed less often than primary mailboxes, the data is still important and has to be preserved without danger of loss. Any loss would undermine customer confidence in Office 365 and that is not a risk Microsoft would take.

Onward in 2017

While you’re waiting for expandable archives to be available to your tenant, Microsoft support can increase the standard quota assigned to archive mailboxes from 100 GB to 170 GB. That might not be enough for some, but I suspect that it’s sufficient for the vast majority of users.

After all, it takes time to accumulate more than that amount of archive data – unless you’re trying to migrate from legacy email archives, in which case you’ll just have to wait until Microsoft restarts the deployment (anticipated in “the first quarter of 2017”). Alternatively, you can go ahead by splitting your migration load over a larger number of “regular” archive mailboxes.

Follow Tony on Twitter @12Knocksinna.

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