Posts Tagged ‘DR’
Too often, business continuity planning and disaster recovery planning are treated as the same functions. Unfortunately, they are not. Business continuity planning helps organizations insure that applications and processes continue through the myriad of day-to-day disruptions that might occur. These include IT component failures, such as disk-drive failures, a server failure, a dropped network link, or an application bug. Disaster recovery planning helps organizations recover operations after less frequent, but far more devastating events, such as fires, floods, hurricanes, earthquakes, and a variety of man-made disasters. While the data center strategy is only one component of business continuity and disaster recovery planning, it is a key component. And while business continuity and disaster recovery planning are different functions, they must often be considered together, because of budget limitations.
There are plenty of advantages to having a business continuity data center in region, a very short distance from the production data center. If the data centers are very close, there will be little impact on transaction latency for the always-important two-phase database commit. Failover times from the production data center to the business continuity data center can be very short. Staff that normally work at the primary data center can easily show up for work at the in-region business continuity data center. WAN charges between the primary and business continuity data centers will be relatively low.
The problem with an in-region business continuity data center is that it can’t replace an out-of-region disaster recovery data center. The two are simply too close for comfort. And few organizations can afford three data centers. Following are a few of the types of disasters that can prevent an in-region business continuity data center from acting as a disaster recovery data center:
- Electrical-grid failure
- Telecommunications failure
- Transportation systems failure
- Chemical spills
- Radiation leaks
- War, terrorism, and civil unrest
For these types disasters, it is much more likely that both in-region data centers will be affected and much more challenging to recover applications and data. One of the trade-offs organizations must make is between how quickly they recover and how certain they are that they can recover from the range of disasters that could strike them. We believe that a slight increase in recovery time is well worth the additional assurance that you can actually recover applications after a disaster. Using an in-region business continuity data center as a disaster recovery data center is a little like doing a tandem sky dive. It’s fine, as long as nothing goes wrong.
Tim is the VP of IT. His company’s data center is more than a thousand miles from the nearest ocean, so it’s not going to be impacted by a tsunami or a hurricane. It’s in an area that has very little seismic activity, so it’s not likely to be affected by an earthquake. There are no active volcanoes nearby. It’s not near any rivers or near a flood plain. There are no other major buildings nearby, and, even though his area has experienced a major drought over the past year, the risk from fire, at least from somewhere outside the data center, is very low.
Tim’s disaster recovery plan calls for a full backup of the application and data files of the critical applications once a week and an incremental backup nightly. The backups usually complete without error, but not always. Some applications are considered more critical than others, so some applications are backed up less frequently. Tim does a disaster recovery test twice a year, to make sure that everything in the DR plan is working. Usually it is. There are other risks to his data center. He could lose power or network communication. He could have a fire that starts inside the data center. His area does occasionally have tornadoes, but not very often. There could be a chemical spill that would require the area to be evacuated, but none of these are very likely.
Like every IT director, Tim has a limited budget, and he is constantly under pressure to keep IT costs low. Tim has made a series of guesses, bets really, in developing his disaster recovery plan. He’s bet that he’s covered for most of the risk associated with natural disasters, he’s bet that the applications that he deemed critical are the right priorities, that he’s got all of the program files and data together in the proper groups, and that nothing has changed since he last revisited the plan. He’s betting that the backup process is working, that the tapes are readable and the applications recoverable.
Those are only some of the bets that Tim has made. Each bet has a consequence. Sometimes he’ll win. Sometimes he’ll lose. But what happens, if Tim guesses wrong?
I’m a fan of the movie, “The Princess Bride.” If you haven’t seen the movie, click on the link below to see a short clip of what can happen when you guess wrong.
The Princess Bride: The Man in Black in a battle of wits with Vizzini.
Actually, like the movie, the story I just told you is fantasy. Tim is real, but I made up the rest. In reality, Tim made a very different bet. He bet on Axxana. With one very good bet, he avoided making hundreds of bad ones.