Data Centers

Don't rely solely on remote availability

One popular disaster recovery misconception is that organizations benefit from remote-only failover operations. Mike Talon lists a few reasons why this is a mistake.

Many organizations find the idea of remote-only failover operations very appealing. They view this solution as a way to cut costs while still offering the ability to recover data systems to another location.

However, failing over to (or replicating or backing up data to) only a remote location isn't sufficient as the sole component of a DR plan. Let's look at some of the reasons why this is a mistake.

Potential single-server failure

Many companies fail to consider this possibility. If only one data system fails, odds are good that the remainder of your data center is probably still able to function adequately—if not exactly the same as it did prior to the failure.

The end result is that you may create a situation where you fail over data systems to another location when it's not really necessary. In addition, this can cause extra work for administrators and more downtime for users.

Impact on end users

Failing over to a remote location could change your networking needs and how your end users do their jobs. For example, having to suddenly access data systems across a wide area network (WAN) could cause delays and frustration to your end-user community.

If you experience a data-center-wide emergency, it's very likely that your end users will need to work from alternate locations, affecting productivity across the board and leaving them to deal with potential difficulties with remote access. However, if nothing else is wrong with the environment, you'll likely find them far less tolerant.

Impact on data systems

If a data system fails and other systems rely on immediate connections to the failed system, you'll face one of two choices: Either manually fail over the other systems, even though they're working perfectly fine, or else resign yourself to dealing with the same kind of problems as your end users.

Regardless of which option you choose, it basically means extra work. In addition, there's the potential that mistakes and failures will compound the original emergency.

No automatic failover

Many DR systems that involve replication or snapshot data capture allow you to either fail over automatically or on command. However, it's inadvisable to fail over automatically across a WAN, where a connection break can mimic a downed server situation from the perspective of the DR server. That means you lose the option to automatically fail over if you've implemented no local failover option.

Implementing redundant failover systems at both the local and remote sites can eliminate almost all of these issues completely. And proper configuration of the systems will eliminate the rest.

While these solutions cost more than remote-only solutions, you can recoup those costs in the long run in terms of avoided downtime and fewer accidental failovers. Avoiding up-front costs and setup considerations often results in more pain and lost profits down the road—a trade-off that isn't beneficial technically or fiscally.

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