Tag Archives: Compliance

There’s a bit of misinformation, or lack of information, floating around about the use of Office 365 Personal Archives. This feature, which is included in the higher-end Office 365 service plans (including E3/E4 and the corresponding A3/A4 plans for academic organizations), is often cited as one of the major justifications for moving to Office 365. It’s attractive because of the potential savings from greatly reducing PST file use and eliminating (or at least sharply reducing) the use of on-premises archiving systems such as Enterprise Vault.

Some Microsoft folks have been spreading the good news that archives are unlimited (samples here and here), and so have many consultants, partners, and vendors– including me. In fact, I had a conversation with a large customer last week in which they expressed positive glee about being able to get their data out of on-prem archives and into the cloud.

The only problem? Saying the archives are unlimited isn’t quiiiiite true.

If you read the service description for Exchange Online (which we all should be doing regularly anyway, as it changes from time to time), you’ll see this:

See that little “3”? Here’s its text:

Each subscriber receives 50 GB of storage in the primary mailbox, plus unlimited storage in the archive mailbox. A default quota of 100 GB is set on the archive mailbox, which will generally accommodate reasonable use, including the import of one user’s historical email. In the unlikely event that a user reaches this quota, a call to Office 365 support is required. Administrators can’t increase or decrease this quota.

So as an official matter, there is no size limit. As a practical matter, the archive is soft-limited to 100GB, and if you want to store more data than that, you’ll have to call Microsoft support to ask for a quota increase. My current understanding is that 170GB is the real limit, as that is the maximum size to which the quota can currently be increased. I don’t know if Microsoft has stated this publicly anywhere yet but it’s certainly not in the service descriptions. That limit leads me to wonder what the maximum functional size of an Office 365 mailbox is– that is, if Microsoft didn’t have the existing 100GB quota limit in place, how big a mailbox could they comfortably support? (Note that this is not the same as asking what size mailbox Outlook can comfortably support, and I bet those two numbers wouldn’t match anyway.) I suppose that in future service updates we’ll find out, given that Microsoft is continuing to shovel mailbox space at users as part of its efforts to compete with Google.

Is this limit a big deal? Not really; the number of Office 365 customers who will need more than 100GB of archive space for individual user mailboxes is likely to be very small. The difference between “unlimited” and “so large that you’ll never encounter the limit” is primarily one of semantics. However, there’s always a danger that customers will react badly to poor semantics, perhaps because they believe that what they get isn’t what they were promised. While I would like to see more precision in the service descriptions, it’s probably more useful to focus on making sure that customers (especially those who are heavy users of on-premises archives or PST files) know that there’s currently a 100GB quota, which is why I wrote this post.

For another time: a discussion of how hard, or easy, it is to get large volumes of archive data into Office 365 in the first place. That’s one of the many topics I expect to see explored in great depth at MEC 2014, where we’ll get the Exchange team’s perspective, and then again at Exchange Connections 2014, where I suspect we’ll get a more nuanced view.