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High Availability—Your BlackBerry Enterprise Server's Safety Net

Uptime always trumps downtime

Our vote for the two most terrifying words for the IT administrator is “system downtime.” But thanks to the high availability (HA) features built into BlackBerry® Enterprise Server v5.0, system downtime can become a rare thing indeed. HA setup and management is surprisingly straightforward. And you now can also get HA protection for BlackBerry® Mobile Voice Systems v5 (BlackBerry MVS) and for the Social Networking Application Proxy used with the BlackBerry® Client for IBM® Lotus® Connections v2.5.

This article explains HA and how it works in BlackBerry environments. Considering the benefits, if you haven't set up HA yet, you should do so soon. Bonus tip: Maximizing configuration database availability.

What is HA?

As you probably know, the HA concept is to build redundant systems into an IT configuration. If the main system fails, the second system can step in. The aim is for 24/7 uptime and little or no noticeable interruptions for users.

In practice, BlackBerry Enterprise Server has HA built right in, so it is a straightforward process to set up. (More on how it works below.) For instance, if your primary BlackBerry Enterprise Server instance loses its connection to the Internet, the system can automatically switch operations to the standby BlackBerry Enterprise Server instance, eliminating a costly loss of connectivity. When you notice that a failover has occurred, you can step in and quickly fix the problem on the originating server, set the systems back manually, and avoid potential failover loops.

Why HA is so important

Why take the time to set up HA? Consider this analogy. You pull up to a downtown parking meter. You'll only be 20 minutes and a parking ticket is unlikely. Briefly you consider skipping the 10 extra seconds to drop some coins into the meter. But then you consider the downside to saving those 10 seconds: a hefty $50 parking ticket. The smart move is to not risk it.

The same idea goes for HA in BlackBerry Enterprise Server. True, the system is remarkably stable. Day-to-day system failure is unlikely, and you have other pressing tasks. But taking a little time now to set up HA can prevent loss of connectivity for your BlackBerry® users later.

How it works

Although variations exist, the basic HA setup in BlackBerry Enterprise Server works like this:

  1. Within the same network segment but on separate machines you set up (1) a primary BlackBerry Enterprise Server instance and (2) a standby instance. Together these servers comprise a BlackBerry Enterprise Server pair.
  2. The pair shares the same BlackBerry Configuration Database, which is replicated across two database servers.
  3. The primary instance runs all BlackBerry Enterprise Server services. Meanwhile the standby server connects to the primary server and checks periodically that the primary server is healthy. You can configure the thresholds that determine the health of a BlackBerry Enterprise Server. If the health of the primary server falls below the failover threshold or if the primary server stops responding, the standby server can then automatically promote itself.
  4. If a failover occurs the administrator can then diagnose and correct the cause of the failover on the original system, and then reset the automatic failover capability.
High Availability—Your BlackBerry Enterprise Server’s Safety Net
When it fails over the automatic failover capacity switches off. That is by default because you want to avoid the possibility of the system flipping back and forth. Instead, if a failover occurs you need to diagnose the situation and then turn automatic failover back on.            
- Paul Morley, Technical Product Manager, Enterprise at Research in Motion® (RIM)

Note that either server can run the mobile solution independently of the other, and the solution can support deployment options on both physical and virtual hosts. Both servers use the same Server Routing Protocol (SRP) credentials and BlackBerry Configuration Database. Also, you don't need additional CALs (client access licenses) to run in high availability mode.

To administer the BlackBerry Enterprise Server pair, you can install the BlackBerry Administration Service with both BlackBerry Enterprise Server instances and configure high availability separately for the BlackBerry Administration Service. (Click here for more information.)

Morley, however, says that for performance reasons you can alternatively install the BlackBerry Administration Service separately from the BlackBerry Enterprise Server pair. “We are seeing some of our larger customers segregate their BlackBerry Administration Services on to their own machines to help distribute the load,” he says.

Steps to install the standby server

Detailed instructions for setting up HA can be found in the Installation and Configuration Guide.

Setting thresholds

As an IT administrator, you have control over the BlackBerry Enterprise Server HA environment. “Health parameters are highly customizable to your environment. You can change the order of them to better adjust to the needs specific to your environment,” says Morley.

These can include:

  • Wireless access
  • Messaging server connection
  • Web content access
  • Address look-up
  • Calendar synchronization
  • Attachment viewing
  • The ability to push application data to BlackBerry smartphones.

By default, these threshold levels will automatically failover to the standby server if the primary server loses its connection to the BlackBerry infrastructure, messaging server, or the Internet.

Example: What happens after the primary server's health score falls below the failover threshold?

In this scenario, the standby server first confirms that the health score of the primary server is below your organization's pre-established failover threshold. If yes, the standby server then confirms that its own health score rates above both the promotion threshold and the primary server's score.

If the answer to both requests is yes, then the standby server sends a demotion request to the primary server. The primary server then demotes itself, allowing the standby server to take over the active connections to the configuration database, messaging server, and SRP connection to the BlackBerry Infrastructure. Afterwards, the standby server writes its identity as the primary BlackBerry Enterprise Server to the BlackBerry Configuration Database.

HA in a distributed environment

When you install multiple BlackBerry Enterprise Server components on different computers as part of a distributed environment, you can configure the entire system for high availability. This requires that you install two or more instances of the HA components in your organization's distributed environment so that when one instance stops responding, the others can take over. See the table below for more information.

Component HA type
BlackBerry Administration Service Load balancing using DNS round robin, or a hardware load balancer
BlackBerry Attachment Service high availability Load-balancing with primary and secondary groups
BlackBerry Collaboration Service Failover with an active connection to one instance and standby connections to other instances
BlackBerry Configuration Database Database mirroring
BlackBerry MDS Connection Service Failover with an active connection to one instance and standby connections to other instances
BlackBerry MDS Integration Service Load balancing with DNS round robin or a hardware load balancer
BlackBerry Router Failover
BlackBerry Monitoring Service Does not support high availability. If you install two or more BlackBerry Monitoring Service instances in your organization's environment, only the first instance is used.

Maximizing configuration database availability: Best practices

  • Where to store: When configured for high availability, both the primary and standby BlackBerry Enterprise Servers connect to a BlackBerry Configuration Database. If the primary server experiences a hardware failure, the standby server might not be able to access the database, which would prevent it from promoting itself to the primary server role. Therefore it should be stored on a remote SQL server that’s separate from the primary server.
  • Database mirroring: BlackBerry Enterprise Server v5.0 also supports database mirroring, which can take your organization's HA environment to another level by allowing complete system redundancy as a defense against catastrophic server failures.

    As long as you install the same version of Microsoft® SQL Server® on both the primary database and the mirrored database—and configure the same permissions on both—the mirroring process duplicates the database in real-time. This mirroring process also requires the use of a third server (the “witness”) that enables the mirror server to recognize whether to instigate an automatic failover. Should the principle configuration database fail, the BlackBerry Enterprise Server components will automatically connect with the mirrored database. Click here for more details on database mirroring.
High Availability—Your BlackBerry Enterprise Server’s Safety Net

HA in BlackBerry MVS v5

Starting with version 5.0, BlackBerry MVS also offers HA features. It consists of an active BlackBerry MVS Session Manager and a standby BlackBerry MVS Session Manager. You can use high availability to help provide minimum downtime for BlackBerry MVS users if one of your organization's BlackBerry MVS Session Manager instances stops responding or requires maintenance. The failover process is designed to be automatic, but you can perform a manual failover before you perform scheduled maintenance.

High Availability—Your BlackBerry Enterprise Server’s Safety Net

As the nearby diagram shows, when you configure the BlackBerry MVS for high availability, you install the BlackBerry MVS Console, active BlackBerry MVS Session Manager, and standby BlackBerry MVS Session Manager on different severs in the same BlackBerry Domain. Both BlackBerry MVS Session Manager instances use the same BlackBerry MVS Console and BlackBerry Configuration Database.

Get more details at BlackBerry MVS high availability.

HA in the BlackBerry Client for IBM Lotus Connections v2.5

The Social Networking Application Proxy used with the BlackBerry Client for IBM Lotus Connections v2.5 also offers HA. The application gives highly secure enterprise social networking capabilities for people-based collaboration.

High Availability—Your BlackBerry Enterprise Server’s Safety Net

An HA architecture is possible when more than one Social Networking Application Proxy server is deployed, such as in a high capacity infrastructure. In the event that one of the Social Networking Application Proxy servers becomes unavailable due to malfunction or maintenance, high availability infrastructure allows server traffic from the unavailable server to be routed to the functional server.

High's yours to shape

BlackBerry Enterprise Server software anchors your organization’s mobile and wireless communication environment and its built-in high availability architecture can dramatically reduce productivity-killing downtimes (planned or unplanned). As an IT administrator you can shape your own BlackBerry Enterprise Server high availability experience by setting custom failover thresholds and configuring the BlackBerry Enterprise Server components to best complement your company or organization’s existing server structure.

How to get more information

BlackBerry Enterprise Server Planning Guide (PDF) »

High Availability thread in the BlackBerry® Support Community Forums »

Understanding High Availability for the BlackBerry Enterprise Server »

BlackBerry Enterprise Server Express

Support Forums

The BlackBerry® Support Community Forums are a great place for your BlackBerry device users to get help—and a place for you to connect with other IT administrators. Do you have questions about BlackBerry Enterprise Solutions? Are you looking for support on devices or accessories? Visit the BlackBerry Support Community Forums.