In praise of the humble archive mailbox

I have concluded that I like archive mailboxes. At least, I like them a lot more than I like PSTs. You might disagree, but that's your prerogative. And given the size of the quotas available to Exchange mailboxes today (especially in Office 365), it's entirely reasonable to want to keep everything in your primary mailbox. But that's a little untidy as you don't really need to carry around every read-receipt you have ever received, do you? The downside with archive mailboxes is that they can only be accessed online. It can be a bit slow sometimes to fetch something - or even worse, put something there. But even these issues don't take away from the essential goodness of archive mailboxes as the place where stuff can be put for ever and ever and ever...

A recent Microsoft blog lauded the wonders of online archives, specifically of the type made available in on-premises Exchange and Exchange Online (just in case you thought otherwise). Interestingly, the post says that “studies suggest that three-fourths of an organization’s intellectual property is contained within email and messaging systems.” 

I guess along with all of that valuable intellectual property, mailboxes often also hold a whole heap of dross. At least, that’s the conclusion you might reach if you examine the contents of the mailboxes revealed in the infamous Sony hack or even those recovered from the Enron fiasco and now mainly used for test purposes.

But joking apart, it is true that people keep an incredible amount of information in their mailboxes and, in many cases, use Outlook to organize all that data. I know I do, which is why I am so happy that Outlook 2016 is so much more accurate at searching. The crazy search results generated by Windows Desktop Search in previous versions of Outlook appear to have been stamped out by Outlook 2016 using online searches whenever possible.

Microsoft’s post goes on to make the case that archives help people with storage, data restoration, security, productivity, and compliance. I agree with most of the assertions, even if the point around data restoration is weak. In any case, I think the main thrust us that we have archive mailboxes and should make good use of them, which seems like a reasonable stance.

If you use either Exchange 2016 or Exchange Online, archives can act as black holes for information as Microsoft has engineered a self-expanding capability into these mailboxes. I suspect that Microsoft will do the same for primary mailboxes in the future, but only after the engineering work has been done to understand how to expand a repository that is in a constant state of flux. The kind of mailboxes that will need to auto-expand are likely to be the largest and busiest as they are the ones that will need the extra capacity. On the other hand, archives are often left alone for years.

Good as archive mailboxes are, I keep on running into two problems when the time comes to convince people to use them.

First, archives are only ever available when an online connection is available. In our always-connected world, this might be considered less of a problem than before. That is, until the time comes when you need an item that’s in an archive mailbox and the WiFi connection you depend on proves to be a tad unreliable. People like the ability to synchronize the entire contents of their primary mailbox into the Outlook OST because it means that everything in the mailbox is available all the time.

To some degree, this problem becomes less important as people keep more in their mailboxes, simply because in practical terms it is impossible to keep very large mailboxes synchronized and available offline. For instance, synchronizing a 100 GB monster into an OST will a) take a long time and b) give the OST a real performance challenge, especially if it’s not held on an SSD. Microsoft has done their best to encourage people to think about how much data they really need for offline access with the OST “slider” in Outlook 2013 and Outlook 2016. However, people still seem to synchronize too much – just in case.

The second problem is that archives are slow to access whenever you need to retrieve an item or, even worse, if you attempt to use Outlook to drag and drop an item into a folder in an archive mailbox. Each time I use Outlook in that manner, I find myself saying that moving items into an archive mailbox is firmly in the “I wish I never did that” category.

I suppose that a lot of activity is going on behind the scenes to allow Outlook to connect to whatever database the archive mailbox is stored and then to move the item. This is fine, if only things didn’t all happen so slowly and Outlook didn’t completely freeze while the operation proceeded. It would be nice if this kind of interaction was handled by a background thread.

All of which leads me to believe that the best way to get items into an archive mailbox is to let Exchange do it for you either through retention policies that move items automatically after they reach a certain age or when the Office 365 Import Service ingests PSTs. This processing happens in the background and doesn’t get in the way. Once it’s done, you’ll be able to search and find any items you need in the archive (online searches with Outlook Web App are best if you don’t use Outlook 2016).

Don’t get me wrong though. I still like archive mailboxes – a lot. Because they are available to multiple devices rather than just Outlook (on a mobile device, you can fire up a browser to access the archive if you need to), archives are so much better than the alternative of using PSTs (all of which I would cheerfully eliminate). It’s just that they need to be used in the right way to extract maximum advantage. Which isn’t unusual when discussing technology…

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Discuss this Blog Entry 3

on Feb 24, 2016

Great article, Tony. Do you happen to know if Online Archive Mailboxes in O365 are at the same level of redundancy as regular mailboxes (4 DB copies across at least 2 data centers)?

I was assuming probably not, to help offset the cost of offering users unlimited online archives, but I have not been able to find any details one way or the other.

on Feb 24, 2016

AFAIK, archive mailboxes are mixed in with primary mailboxes in mailbox databases and therefore have exactly the same level of protection (4 copies etc.)

on May 23, 2016

I have a user that managed 6 delegates over the past year and has accumulated 40000 calendar items 21000 sent items folder. Some of the data is as a result of corrupted entries. I have signed up for online archiving on our 365 platform E1 platform. I am assuming the calendar can be archived as well, thus reducing its size. I don't see the calendar option when it creates an archive mailbox.

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On-premises and cloud-based Microsoft Exchange Server and all the associated technology that runs alongside Microsoft's enterprise messaging server.


Tony Redmond

Tony Redmond is a senior contributing editor for Windows IT Pro. His latest books are Office 365 for Exchange Professionals (eBook, May 2015) and Microsoft Exchange Server 2013 Inside Out: Mailbox...
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