This content is part of the Essential Guide: Guide to easing the migration to Office 365

Five reasons for an Office 365 hybrid deployment

Not all organizations can go all-in on cloud. There are five reasons why a hybrid Office 365 arrangement makes sense for those companies.

Administrators who manage older versions of Exchange Server can't always make a clean break from the on-premises...

environment and switch to Exchange Online. Regulatory and technical hurdles make it difficult or impossible to move mailboxes to the cloud or use other services in Microsoft's cloud. An Office 365 hybrid deployment can provide the flexibility needed to avoid disruption.

Microsoft has improved features within Exchange Online, Skype for Business and SharePoint Online. And, in some cases, the cloud versions have more capabilities than on-premises versions.  An Office 365 hybrid deployment lets enterprises keep some data and workloads on premises while using Microsoft cloud services. And most enterprises choose an Office 365 hybrid deployment for five common reasons.

1. IT can migrate at its own pace

A hybrid implementation of Exchange Online lets IT migrate mailboxes without disrupting existing email services, thereby minimizing the effect the project has on the business. Admins can also use a common management console -- the Exchange Administration Center -- to handle tasks for both on-premises Exchange Server or Exchange Online.

2. Companies don't lose existing on-premises customizations

An Office 365 hybrid deployment lets enterprises keep some data and workloads on premises while using Microsoft cloud services.

Some companies use Exchange Server and SharePoint Server add-ons that cannot move to the cloud. Because both online and on-premises Exchange and SharePoint can coexist, customers can continue to use those third-party tools, as well as any custom code that runs in the on-premises infrastructure, while other workloads move to the cloud.

3. IT teams can keep certain applications on premises

A common concern about moving to cloud involves how to handle applications that must remain on premises, such Skype for Business Enterprise Voice and SharePoint local data source. With Skype for Business Enterprise Voice, some organizations are contractually obligated with a public switched telephone network provider that requires them to deliver services through on-premises Skype for Business servers.

4. Meet compliance and security mandates

Microsoft continues to pursue a number of compliance certifications; however, there are still some legal and complex auditing requirements that keep enterprises from moving all of their data to Office 365. For example, governments in other countries often require companies with locations across multiple continents to maintain on-premises deployments for end users who reside within certain borders. These requirements mean companies might keep a portion of their data, such as email, SharePoint data and public switched telephone network, inside the country.

5. Certain services are only available in a hybrid model

An Office 365 hybrid deployment enables companies to use certain cloud services that integrate with on-premises Exchange. For example, there are a number of features available within Office 365 to protect email and archiving that are available only when Exchange is configured in a hybrid mode.

Next Steps

How to patch and monitor a hybrid Exchange deployment

Migrating to a hybrid Exchange environment

How to secure Office 365 and Exchange servers

Dig Deeper on Exchange Server setup and troubleshooting