Right approach to perform Exchange Server (on premises) to Office 365 migration

The process of mailboxes migration from MS Exchange to Office 365 seems to be a very simple and easy task when you know about the complete migration process. Still you may face certain problems or technical glitches while performing the migration process between Exchange servers. 

To execute the Office 365 migration you need to do certain pre-planning, requirements that have to be configured features that have to be worked out, and then lastly selecting the mailboxes to migrate into Office 365. There is one point to notice that there is no standard or general process of migration to Office 365.

Every organization may experience something that can create a problem during the migration process.  These issues are being briefly mentioned below.

1.  Corruption in Exchange environment: The whole of the Exchange Server environment issues need to  be worked out early.
2. No downtime allowed: Sometime, you may come across organizations where employees (Executives or Managerial level) cannot be down on an email.
3. Sluggish network connection: The weak network connection might slow down the upload of Exchange mailboxes to Office 365. The best approach to address this issue is ‘staging’. In this process mailboxes are gradually sweeps up to Office 365 over a period of time.
4.   Strong security: Many organizations where network security is so clinched down that many of the default or inbuilt tools from Microsoft to migrate into Office 365 have to be adjusted to fit within the security guidelines of the organization.
5. Misconfigured firewalls, proxy devices and CAS servers: Misconfiguration at boundary protection can cause corruption in Exchange Web Services.
6. Unsupportive to old Outlook versions:  In order to perform migration to office 365, there are certain rolling requirements. Currently, it is supportive to Outlook 2007 SP3 or higher versions and for Entourage Server its Mac 2008 with SP3 or higher.
7. Legal or compliance policies: The process of migrating user’s mailboxes into cloud based environment is new for organizations. And there are always many queries or questions about addressing security and compliance policies.

Now, there are many more practical issues with their solutions that I had noticed during migration:

      a)    Slow process of Mailbox Migration: Suppose you were performing the mailboxes migration that is running really slow (about 4-5 mailboxes a night) rather then 50-300 migrations generally, you may think that poor network or internet connection is the root cause behind such a bad performance.

But the reasons are completely different. Odd configurations of firewalls, security settings and migration server problems are the main causes. So a proper preplanning and testing is very necessary to avoid these issues.

      b)    Worked fine in the lab: When an organization setup a test lab and test an Office 365 account and perform everything in test and it works fine, so a lot of practical situations have been uncovered from these situations like: the lab internet connection has less traffic than the production internet connections; or test mailboxes have no corruption while real mailbox might be infected from corruption; or lab servers don’t have security layers while real professional servers are incorporated with various security policies. Moreover lab testing doesn't rectify the results which can generally be experienced on the production level.

       c)      Email Archives: Many organizations have incorporated email archiving vendors but no one has method of getting emails out of their archives. Since a long time, you’ve been stuffing emails into archives, creating stubs in Exchange and archiving attachments, moving archives to cloud based environment. 

But if you want to avoid this lengthy procedure, you just need to move all your emails (and archives) to Office 365 which provides you with a virtually unlimited archive storage plus extensive eDiscovery.

     d)    Bad Advice: When an organization installs Exchange 2013 server (as advised from consultant) as a hybrid server when they already had a perfectly working redundant load balanced Exchange 2010 SP3 CAS array. Further, this installation takes place at a different site from where the servers are normally active.

Lastly, I would like to suggest that the process of Exchange Server (on -premises) migration to Office 365 should be performed by keeping in mind all the pros and cons associated with it or under the supervision of an expert.