Microsoft Exchange is the market leader among corporate messaging systems. It offers a wide range of capabilities and, with the introduction of Exchange 2007, offers unified communications capabilities that a growing proportion of organizations are adopting. However, Exchange does not stay up and running 100% of the time despite the best efforts of those charged with managing it.

One solution to ensure that Exchange remains available is the Teneros Application Continuity Appliance. One appliance is deployed for each Exchange Server. The appliance maintains an object-level backup of the Exchange mail store and also performs error-checking while replicating the data to ensure that the copied data is not corrupted. When the Exchange server hiccups or fails altogether, the Teneros appliance activates to provide what is essentially a hot standby for virtually instant failover.

The Teneros appliance offers a number of advantages for disaster recovery or even routine maintenance that brings down the system. Not least of these advantages is that failover is transparent to end users, allowing them to continue working. There is no requirement for installing software on the Exchange server and an appliance can be installed with minimal effort on the part of IT staff. Plus, Teneros will remotely monitor and update each appliance to keep it running with a minimum level of reliability that the company claims to be at least 99.99% (no more than five minutes of downtime each year).

Any organization, regardless of its size, should implement a sound disaster recovery strategy and product set that can keep its e-mail servers operating as close to 100% of the time as possible. The Teneros Application Continuity Appliance is one of several very good solutions that Exchange-enabled organizations should put on their short list to consider.

Editor's note: Starting Tuesday, Nov, 13, the Unified Communications newsletter will be merged with the Antispam News Alert and will be named the "Unified Communications Alert." Subscribers to the HTML version of this newsletter will notice some enhancements that will provide you with access to more resources relevant to unified communications. You will still receive Michael Osterman's analysis of this market, which you will be able to read in its entirety online at NetworkWorld.com, along with links to relevant news headlines of the day. We hope you enjoy the enhancements and we thank you for reading Network World newsletters.

Michael Osterman is principal analyst of Osterman Research.