Deploying Hybrid Cloud Email: What You Need to Know

Email/calendar systems are the most important communications channels for enterprises, and deliver a reliable, cost-effective and secure mechanism for collaboration. An email system is typically used for a decade before suppliers are changed: organizations should apply significant due diligence in selecting an email system, given the criticality of email to their overall health.

Companies are hearing the "siren song" of cloud email and, despite its immaturity, pressure is on organizations to tap into what is perceived to be a superior provisioning model to on-premise deployments. While cloud email is still in its infancy -- at three per cent to four per cent of the overall enterprise email market -- we expect it to be a growth industry, reaching 20 per cent of the market by year-end 2016, and 55 per cent by year-end 2020.

Escalating demand for hybrid model

That said, the cloud model for email services has not been suitable for many organizations that look for flexibility to support custom deployments. Organizations are also looking for systems with the ability to meet specific security, content control and application integration needs. Consequently, we see escalating demand for hybrid models -- where some mailboxes "live" in the cloud and others are located on premises.

A hybrid model helps organizations cope with the immaturity of the cloud model, while still allowing some use of the cloud. In a hybrid model some mailboxes live on-premises and some in the cloud, and it relies upon a user segmentation model, where different email services are offered to users based on need, as opposed to offering the same email to all users.

It has been our experience that running a hybrid model using different vendors results in complications for directory synchronization, help desks, format translation and policy enforcement. Dual-vendor deployments can also lead to a lack of interoperability for features such as calendaring. Dual-vendor hybrid models, therefore, are generally best avoided.

At this point, however, hybrid email models are in their infancy. Microsoft, for example, is only now offering rich coexistence between premises-based and cloud-based deployments. Given its infancy, then, organizations must be very careful when contemplating using a hybrid model.

The following are some of the important considerations when considering hybrid models:

User provisioning -- Large organizations have built very efficient processes for account creation of email services. Those processes will need to be extended to support cloud-based email services.

Management -- A single console for managing both on-premises and cloud email is required for efficiency and consistency of management and administration. Scripting services for bulk changes need to be supported across both provisioning models.

Single sign-on -- The ability for a user to authenticate to a local directory and have the credentials to enable access to the cloud email service is required.

Interoperability -- Common email functions -- such as free and busy calendar lookups, calendar and mailbox delegation, distribution lists and contact sharing -- must be able to span both provisioning models.

Application integration -- There may be a requirement for simple application needs -- such as receiving voice mail in the in-box -- to be uniformly available across both cloud and on-premises models.

Help desk -- Help desks will need the same access rights, problem resolution scripts and escalation procedures for both models.

Security -- Common security needs -- for example, for multifactor authentication, TLS, password rule enforcement, virus scanning and access to logs -- will need to be consistent across cloud and on-premises deployments.

Content control -- Integration with records management, data loss prevention, keyword filtering and archive services should span both models.

Federation -- Companies often federate email services with business partners to create collaboration efficiencies. Cloud services should support the same federation services as the local model.

Versioning -- Organizations need to be cognizant of the implications of the different software versions. Microsoft, for example, requires that an Exchange 2010 Client Access Server be deployed in an Exchange 2007 infrastructure to accommodate full hybrid services with Exchange 2010 in the cloud.

Licensing -- Cloud suppliers must accommodate the business requirement for a single license agreement covering both models.

Redundancy -- Directory links and network paths between on-premises and cloud systems need to be fully redundant to eliminate single points of failure.

Rumors of the death of email continued apace, but we maintain our position that social media and email are on a path of co-evolution and convergence, rather than a zero-sum game. There is also the insidious notion that email is a commodity, which we believe leads to an underestimation of the complexity of email, and hence a lack of due diligence in evaluating cloud email services.

About Matthew W. Cain

Matt Cain is a vice president at Gartner, where he is the lead email analyst. His coverage includes all collaboration modalities as well as collaboration theory. Cain has focused on the email market for more than 20 years, watching it shift from mainframes to LANs to client/server platforms. He no focuses on helping organizations determine when moving email to the cloud is appropriate.

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