Why migrating to hybrid Office 365 makes sense

If your company needs some services on-premises, a hybrid Office 365 configuration may make sense. Here's the impact of various services, from SharePoint to Exchange to PowerApps.

Fully moving to cloud-based solutions is challenging. Most companies house legacy data and applications that may not be easy to move to the cloud. Others, though an increasingly smaller number, may have concerns about data privacy in the cloud. And others are just not yet ready to migrate, given their volume of data or customization requirements.

As a result, many firms opt for a "hybrid" approach, meaning they split services and/or software between their on-premises data center and a cloud provider. In other words, the organization isn't moving an entire software or service to the cloud; they will continue to run some portion of it on-premises just as before.

In cases where companies choose a hybrid configuration for their applications, hybrid Office 365 is an option, and it's important to understand what that means for your implementation.

What does "hybrid" mean for Office 365?

Office 365 is not one product, but a suite of applications. You'll need to configure the products individually for their specific hybrid configuration, and there are varying options for hybrid Office 365 setups depending on the product.

Microsoft describes most of the original Office 365 products as "hybrid-compatible," including Exchange, Skype for Business (originally Lync), SharePoint, and OneDrive (formerly SkyDrive). These products started their lives as on-premises products. As a result, they'll be the basis for your hybrid implementation.

Every implementation starts with Active Directory (AD). When you consider Office 365, AD may not leap to mind, but this directory service is critical to all Office 365 deployments. You can connect on-premises AD to Azure AD in two ways: AD Connect (synchronization) or AD Federation Services.

For situations in which you want to maintain AD primarily on-premises, you can use AD Connect, which allows you to "synchronize" identities between Azure AD and on-premises systems. This synchronization can be done with or without storing your passwords within your tenant, but it allows for single sign-on like capability.

Firms can achieve a true hybrid configuration by implementing AD Federation Services. This configuration allows your on-premises and Office 365 tenants to share identities and take advantage of integration with Office 365 services, as well as integration with services from Box, Dropbox, Slack and others.

Exchange is compatible with a hybrid Office 365 setup. It has a distributed architecture and can be configured to live across your on-premises data center and Office 365. When integrating with Office 365, you can take advantage of this architecture by splitting workloads between an on-premises implementation and the Office 365 tenant. For example, for any given mailbox population, you can house a portion on Office 365 and a portion on-premises. This scenario works well when you're migrating from on-premises to Office 365, but it also works well as you're testing the service for use in your organization.

SharePoint's hybrid setup is slightly more complex. SharePoint farms cannot live in two places; instead, you'll need to have distinct SharePoint farms. Each farm should be designated to handle specific collaboration workloads. For example, your on-premises SharePoint environment may cater specifically to your intranet or more secure content. Your Office 365-based SharePoint environment may focus on external collaborative scenarios, especially where third-party collaborators are involved. In this way, each farm is dedicated to a specific purpose, and it's clear to users where to go for specific capabilities. This is true just below the surface, as well, where certain features will automatically operate from one farm or another. A quick reference for hybrid SharePoint implementations can be found on Microsoft's support site.

The one partial exception to workload splitting is hybrid SharePoint search. Challenges that arise from the disconnect between SharePoint sites can be mitigated using search. SharePoint can use the on-premises farm to crawl content and then replicate the index to Office 365. This can help overcome the content source challenges in the Office 365 search configuration and create a unified set of results across both farms. This also helps to unify metadata applications across content within sites, regardless of where they're sourced.

The last product that supports some form of hybrid implementation is Skype for Business (formerly Lync). Somewhat like Exchange, Skype for Business supports users in both environments. The difference between Exchange and Skype for Business is the distinct functionality. In essence, Skype for Business is an instant messaging platform and a telephony platform. When considering a hybrid solution, your initial decision is about where users will "live." Firms can move users from on-premises to their Office 365 tenant and back again. This allows organizations to choose when users can take advantage of basic Skype for Business capabilities. But if firms also use Skype for Business for telephony, there are other considerations.

Telephony is a feature that has been included for a long time. However, as Microsoft refines this functionality, the hybrid telephony approach has come to require more planning. In short, if an organization moves users to Skype for Business in hybrid Office 365, it needs to consider whether telephony is included.

Cloud or on-premises only products

Like many software as a service offerings, Office 365 does have some products that don't have an on-premises equivalent. Products like Sway, Yammer, Bookings, Flow and PowerApps are available online only. These apps were initially "born" in the Office 365 suite and Microsoft has not released an on-premises equivalent. However, this begs the question -- what about hybrid solutions?

The short answer, for some of the services in Office 365, is that there isn't a hybrid option. These products will live exclusively in an organization's tenant. It's up to the firm how to use (or not use) these applications for collaboration and communication needs. This may create confusion across a firm's user population; however, using common domain names and mobile apps should mitigate this issue.

Key considerations

Many products within the Office 365 suite are hybrid compatible. The foundational products, like Exchange, AD, SharePoint and Skype for Business, can all integrate with their on-premises equivalents. However, each requires a slightly different approach. It's critical to effectively plan what you will run and how you will run it in a hybrid environment.

However, as Microsoft has improved Office 365, hybrid configurations have become more challenging. There are Office 365 services that are online only. These services are and will be compelling to users. It's critical for firms to develop an approach to getting value from these tools. Good governance and adoption principles will be the key to success.

Next Steps

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