Organizations, sometimes, remain with the hybrid setup for a long period of time even after migration of data from their local Exchange Server to Office 365 (Microsoft 365).
A long-term hybrid setup can be unavoidable due to operational constraints, compliance, and other regulations where a local Exchange Server must be in place. In this article, we will discuss the reasons for opting for a long-term hybrid setup, outline the challenges associated with it, and explore how to overcome these challenges using an Exchange migration tool.
Reasons Why Organizations keep the Exchange Hybrid Model after Migration
There are many reasons why you would keep the Hybrid Exchange Server setup after the migration to Office 365. Let’s look at the most common ones.
Local Active Directory and Dependencies
When having a local Exchange Server setup with a hybrid setup, you would need to have Entra Connect setup which would be responsible for the synchronization of identities. This will synchronize all the needed attributes which can get quite complicated. A hybrid setup relies heavily on the Entra Connect synchronization. For this reason, after all the mailboxes have been migrated to Office 365, you would keep at least one Exchange Server since Microsoft Entra is not the authority source.
Legacy Application with Email Workflows
There could be a number of applications which are dependent on the local Exchange Server, like Enterprise Resource Planning (ERP), Customer Relationship Manager (CRM), enterprise image scanners, monitoring appliances, etc. Such applications can either integrate with the Exchange Server while also using the Exchange Server as local SMTP relay. Lately, Office 365 has decommissioned the legacy email relay service. Therefore, you would need time until the applications and services can support OAuth. Since this can be time consuming and requires a lot of development effort, it would be more viable to keep an on-premises Exchange Server running.
Compliance, Governance, and Regulatory Requirements
Meeting the compliance and regulatory requirements can be a challenge, especially for industries in the finance, health, and medical organizations where local journaling, message tracking, and long retentions are required. In Office 365, due to some limitations, some of these policies would either not be possible or require a longer testing and possibly further investment into compliance tools and subscriptions.
Phased Migrations
A hybrid migration method is one of the smoothest native methods but it is also the slowest migration method. A hybrid coexistence also allows seamless mail flow between the local Exchange Server and also for the free/busy lookups and a unified Global Address Book (GAB). This could also get complicated to maintain. Moreover, issues with the hybrid configuration can cause a number of operational issues.
Public Folders and Archive Data
Public folder and archive data can take a lot of storage, especially if you have enabled the email journaling on the local server. This should be a problem for on-premises server as one is in control on the level of limits and quotas. For this reason, you would have a hybrid system. As both the on-premises server and cloud act as one, you can choose to leave the archive data and public folders locally due to their size and other features.
Migration Issues and Risk Uncertainty
Apart from the benefits of hybrid system, you must also consider the issues that you might encounter during the setup, migration of data, and post-migration. Data is the most important thing for a company. While migration to Office 365 would be a great benefit for the operations, collaboration, and accessibility of services and data, a botched migration or using the wrong migration method, or complications during the migration, can cause a lot of issues as well as data loss and business disruption. So, you have to keep the hybrid setup configured as there could be uncertainty when it comes to data integrity and that all the data has been migrated with minimal impact.
Challenges of Keeping Exchange Hybrid Setup
There could be a number of challenges you can encounter when keeping a hybrid setup. Let’s list a few of them.
- Keeping a hybrid method will increase the operational and capital cost since you still need to maintain a local Exchange Server, including the hardware, certificates, monitoring, patching, backups, and disaster recovery.
- If the local Exchange Server is out of support or end of life, it will expose the setup to security risks. This would need to be constantly monitored and secured to ensure a strong security lockdown to avoid any unwanted breaches.
- Finalizing the final stages of the migration can be a little bit tricky, especially for public folders, archives, and applications, which are difficult to move or are essential for the operations of business.
How to Ensure Data Integrity when Migrating to Office 365?
To migrate data from Exchange Server to Office 365 with complete integrity, you should consider third-party Exchange migration tools, such as Stellar Migrator for Exchange. The tool offers seamless migration options and supports all versions of Exchange Server and complex configurations, such as Cross-domain and Cross-Forest. It offers incremental (delta) migration to ensure that only new or modified data will be migrated, thus reducing the risk of throttling and minimizing the effort and bandwidth needs.
The tool allows you to migrate user mailboxes, user archives, shared mailboxes, and public folders, with features like automatic mailbox matching, real-time and post migration reporting, hassle-free configuration, and a very easy-to-use interface.
Conclusion
As you have seen, there are a number of factors that you should consider when keeping the hybrid model for a long time. Risks and challenges should be considered in order to mitigate any issues that you might encounter. You should also keep the right Exchange migration tools, such as Stellar Migrator for Exchange, in hand that can directly migrate data from local Exchange Server to Office 365, thus reducing the impact on the business and ensuring a smooth transition