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Top 6 considerations when migrating email and archive data into Office 365

Jun 14, 2018 by Billie Bachra

This blog was guest written by Dr Billie Bachra. Billie is a Principal Consultant at Adept-tec, a  trusted Quadrotech migration partner since 2013. These are her top 6 things to consider when migrating email archives to Office 365.

1. Do I want to move all my data?

Migrating data is a bit like moving to a new house, do you get the removers in and move all your stuff or do you DIY and shift through the contents and take what you need? Many people argue that you take it all because what you don’t use can be put into the secondary mailbox (archive).  We are not so convinced by that argument.

Over the years you will have archived a large amount of data and like most administrators probably haven’t deleted any of it.  A lot of the data in the mailboxes or archives is no longer of value or use, and remember GDPR requires that personal data is not held for longer than necessary. Another consideration is that most archived data is de-duplicated and compressed, so if you have 1TB of archived data, this is likely to be 1.2TB – 1.5TB once the data has been re-hydrated. Another consideration is the time involved in migrating the data. There are generally throttling limitations into Office 365, even if you ask Microsoft to modify them, so it will take more time to move everything.  We are not advocating a deep cull, but rather to review the content and make some key decisions at the start of the project.

Going back to the house moving analogy – moving everything involves hiring more removal vans and more people to move your valuable items and your junk from one place to another. And just because there is essentially ‘unlimited’ storage in Office 365, one day you may find that in future that may no longer be the case.

2. What do I do with my legacy archiving systems?

All the time and resources that were put into your archiving solution can now be freed up but remember that you may still have data that has not been transferred or users that are on long term leave that may still want to access the data. We recommend that you do not de-commission the legacy environment for at least 6 months and preferably wait a year. You will also have freed up storage resources, Exchange resources and backup resources.

3. How do I keep end users trained and informed?

This is vital to a successful migration. End-users complaining, especially very powerful users can put the whole project on hold. Communication is the key here, not just once but throughout the whole project life cycle. Many users will want to know why changes are being made and what’s in it for them. We suggest that you implement the solution in a step-by-step approach. This can be done by either introducing a pilot for some key (friendly) stake holders (the IT department is not always the best for this!). Alternatively, introduce users to the concept of searching for items so that by the time they move into Office 365 they are not reliant on shortcuts to access data. Run short training webinars or create on-line training that must be reviewed before the users are given access to their new mailboxes.

4. What shall I do with all my legacy data?

Once you have migrated your data, even if you make the decision to migrate everything, you will still have inactive data. This could include users who left the company many years ago, data that may have been archived from older systems, and data that you didn’t even know that you had!  That also includes data in the archives that may be in shared mailboxes. You will need to have a strategy in place. At the start of the project you may not have a complete picture of what is active and what is inactive data, but during the process it will become clear, as you unpack your archived or mailbox environment.

5. What about Compliance and e-Discovery?

Office 365 has built-in options for data compliance and e-Discovery but remember that some of the resources that had been put into the on-premises solution will need to be deployed to maintain the Office 365 environment. You may want to still consider having an on-premises solution so you’re not putting all your eggs in one basket. One option would be to use the on-premises solution that you have already and run a hybrid environment. This would enable you to journal all your Office 365 mail into Enterprise Vault either by keeping journal archiving if you already have it in place, or SMTP archiving directly into Enterprise Vault and by-passing your Exchange on-premises solution. With either solution, you will be maintaining only the Journal /SMTP archives and not user archives which will simplify your archiving requirements.

6. What about PST files? Can they be migrated into Office 365?

You may have a large PST file environment that you never got around to migrating into your archiving solution and the good news is that this can be migrated directly into Office 365. I am sure that there aren’t many administrators that would be sorry to see the end of PST files! This is a whole topic that I will cover in a future blog, but the key to successfully migrating PST files to Office 365 is running a discovery process to find out where they are and how much data is in them. You will soon realise that there is far more than you ever imagined. A lot of the content of the PST files will inevitably be duplicate data and we have sophisticated tools that de-duplicate data during migration, either within the files or across all the files that belong to the user. In this case, this will result in the opposite of migration from the archive into Office 365, with PST migration you will end up moving less data into Office 365 due to de-duplication and by applying filters to remove irrelevant data (for example age of content). You will also free up resources such as storage space, back up requirements and reduced calls to the service desk.

Adept-tec was established in 2010 as a premium provider of professional services around the Enterprise Vault product suite. In addition, Adept-tec has rapidly become the go-to specialists for data migrations. We cover pre-sales, initial design and analysis, to implementation. Adept-tec has been a trusted Quadrotech migration partner since 2013. Learn more at