BEFORE, DURING or AFTER. When should an email archive be moved?

Many companies are considering their cloud based email strategy – be it on premises, private cloud or public cloud and Microsoft is certainly ahead of the pack with the Office365 live mail offering.  The good news is there are a vast array of IT companies skilled in providing migrations of live mail to Office365 however, the bad is that not many are skilled in best practices for archive migrations.

This lack of knowledge often manifests itself in advice being provided, varying from “manually export the data” and “don’t worry about the archive until after primary mail is complete” to “let the data expire and don’t bother migrating”.  Sometimes this advice is appropriate however, in the vast majority of cases, these options create enormous headaches when a project commences. We have had countless examples of customers who have planned, budgeted and about to start the live mail migration only to find either the archive has not been adequately considered or that the approach they thought would work is not feasible.

We have explored the “Manual or Automated” in more detail [download id=”2416″]. What we are yet to explore is the order of a migration. Once the approach (manual or automated) has been determined, here are some very good rules of thumb that can be used (of course assuming you are licensed for the online archive):

Exchange 2010 and above Sources in Hybrid mode

If the source is Exchange 2010 or greater AND the environment will be in “hybrid mode”, archive migration should be done BEFORE the primary mailbox migration.  Hybrid allows for the pre-provisioning of the online archive target in O365, enabling the archive to move independently of the live mailbox, taking them out of the critical path. Archives can be migrated first with the online archive being made available to the user and then, on the night of the live mailbox move, the archive can be synchronised.  This approach provides the least user impact.

Exchange 2007 or below

In these scenarios, a third party tool of sorts is often used to facilitate the “co-existence”. In these scenarios, the archive needs to be moved DURING the live mailbox as there is no way to pre provision an online archive.  Therefore, the live mail needs to be moved and the archive immediately thereafter. Sometimes if the volume of data in the archive is excessive, 3 or 6 months of archives are moved immediately following the live mailbox and the balance of messages are trickled in over the subsequent days.  In all cases, when the user logs in after their mailbox migration, they will have access to some or all of their archives.

In both of these scenarios, the user archives are moved either before or during the live mailbox migration and happen as a part of the mail migration project. In no circumstance are they moved AFTER live mail as doing so would deliver a terrible user experience such as shortcuts broken, mail not being able to be found, mail needing to be searched in multiple locations and more.

Other approaches need to be taken when the source mail platform is Notes however the same principles apply. If you are concerned about user experience, the archive must be dealt with as a part of the live mail project and should not be seen as an after-thought or as a separate project. If for some reason user experience doesn’t matter (and would you believe we have had clients who did not care about the impact to the users!) then you would be right in taking the advice that says “we will deal with it later”.

The only archive that could or should be moved “after” the primary mailbox migration is a journal archive as this has little to no impact on the user experience.

Watch out for our blog on PST Files, and if they are still relevant.

Simon Alit > Data Migrations specialist

Simon Altit

Director – EMEA




+61 433 232 349

+44 7403 599 817

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