Moving to Office 365? Prepare for the huge pain of archive migration

Many Exchange admins forget all about their email archives when migrating to the cloud -- at their peril

As an Exchange MVP, I get calls, emails, and tweets daily from people looking for help in making the decision of whether they should go to Office 365 (with Exchange Online) and then how to go about making that move -- PST capture, migration, ingestion, and so forth.

For my own education, I've been reaching out to various support organizations on what pitfalls they are seeing in migrations. This week, I spoke with Rocco Seyboth, senior vice president for intelligent migration at Nuix. That company does migration all day long. He says most IT pros know to ask the standard questions like how to move mailboxes, calendars, contacts, and so forth. But they regularly forget to ask about their legacy archive. It's the invisible elephant in the room.

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There are many email archive tools -- Enterprise Vault, SourceOne, Autonomy, and so on. Whichever one you use, you'll encounter several problems when you move to Office 365.

The first is that your archive tool simply doesn't work (or work well) with Office 365. You move the mailbox to the cloud, whch breaks the stubs, so users can't access those archived emails. That legacy archive is suddenly worthless. Of course, there are usually workarounds. Symantec's archive tool, for example, will continue to work if you have a fully functional hybrid configuration with an on-premises Exchange environment. But that requirement practically eliminates the reasons for going with Office 365 in the first place.

Another issue that may come up is that journaling for compliance and e-discovery no longer works after migratrion to Office 365. Suddenly, your organization may be out of compliance with internal policies and external regulatory requirements. Again, the archiving vendor's workaround may be something unrealistic like using a hybrid Exchange environment.

If you don't want the nightmare of maintaining a hybrid environment, you may think your only option is to move to a cloud-based archive. There is another alternative: You could leave your old archive in where it is and just start fresh with a new archive for your new Office 365 implementation, but that leads to heavy user disruption because users have multiple locations for accessing archived email, which also causes disruption for compliance and legal people who rely on a single repository. So your only realistic option may be in fact be migrating your archive to the cloud.

If you decide to migrate your archive, you have to decide whether to use the native Office 365 archive or a third-party archive like Mimecast. A key consideration is whether the native Microsoft archive meets the needs, or at least the familiar capabilities, of your legal and compliance. Find out before you decide.

Once you start the migration, you'll likely discover you're spending money to migrate a lot of data you may not need because you have been journaling every email for every person in your company for years and not deleting anything in the archive. You don't actually need all that stuff, but how do you tell the difference now between what you should migrate and what you should get rid of? Some migration providers offer an "intelligent migration" approach to help get rid of the unnecessary content. Be sure to work with your compliance people and your candidate vendors to figure this out before committing.

No matter what you decide to do about the legacy archive, there will be a slight gap between when your users move to Office 365 and when they have access to their archived data again. How long it takes depends on the method you use. One problem with legacy archive tools is that you have to reach in to grab their data, but to do so you need to use APIs that were written to get data in, not out. The result is a painfully slow, single-connection process that often corrupts the data while it is being extracted. Nuix's Seyboth says about a third of such extraction migrations are both painfully slow and full of corrupted data, so it's a big risk.

One suggestion he has is to move your data to Microsoft Azure first (if Microsoft will accept your hard disks and move the data into its data center) and then move it to Office 365 from there. That can be a speedier approach if your Azure and Office 365 instances happen to be in the same data center.

I wish I could tell you that migrating to Office 365 is a snap. It's not. There are many advantages to moving your Exchange to the cloud, but the journey can be a rough one.

This story, "Moving to Office 365? Prepare for the huge pain of archive migration," was originally published at Read more of J. Peter Bruzzese's Enterprise Windows blog and follow the latest developments in Windows at For the latest business technology news, follow on Twitter.

Copyright © 2014 IDG Communications, Inc.

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