Redundancy

The final critical aspect of a solid disaster recovery plan is the planning of the IT infrastructure itself. Whilst you may not always have the luxury to do this from initial systems implementation you can always upgrade and attach redundancy to your existing infrastructure further down the track.

Backup Redundancy is essentially tech-speak for having contingencies. It’s about setting things up right, so that when disaster DOES strike, the recovery phase is as fast and reliable as possible.

High Availability (HA) and fail-over redundancy is particularly important for large businesses with enterprise-grade infrastructure. In this case the cost of implementing redundancy for critical systems is a significant factor and must be considered in the design phase. The scope of such projects should make the deployment of highly available systems more economically viable as the cost of a disaster would outweigh the cost of the initial setup.

HA and fail-over setups can be implemented in many different ways depending on the systems involved and the desired level of redundancy but they all perform the same function and that is to eliminate system downtime. They basically do this in two ways:

• Multiple system nodes in place and online simultaneously performing the same function and managed by a load balancer. If one node goes down the load balancer redistributes its tasks over the remaining nodes in the cluster and the loss of that node is effectively invisible to end users.
• Two or more system nodes designed and configured to perform the same function but only one is online or “active” at any given time. In the event that node fails the redundant node(s) is either automatically or manually brought online and becomes the active production node. This type of fail-over is not always seamless to end users but downtime is largely negligible.

As with most aspects of a disaster recovery plan, the kind of High Availability or fail-over setup that would be suitable for your business needs to be evaluated on a case by case basis and tailored to the requirements and desired redundancy of the client. However, in general some level of redundancy should always be employed with your IT infrastructure because at the end of the day you need to weigh up what the value is of creating/implementing a disaster recovery plan versus the cost to business continuity in a disaster situation.

When considering what should be done in planning for those scenarios you hope never arise just remember. It’s your business and your livelihood. As you probably guessed by now, we do provide backup & disaster recovery services.

This is Part 3 of our 3-part Disaster Recovery Plan feature– skipped ahead? Check out Part 1 and Part 2.