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Silent Corruption and How to Prevent it Through Backup

There’s nothing worse than data corruption, right? All of your important data is suddenly damaged and no longer accessible. Some data corruption errors will throw up errors from the drive or operating system, alerting you to the problems that are happening. However, something called silent corruption exists. It sounds sinister, but it’s essentially just data that is now unreadable and has been corrupted without any warning. You’ll want to nip this in the bud as soon as you realise, because it’s possible that the corruption can spread to the rest of your data.
According to a NEC whitepaper, around 10% of major system failures have silent corruption linked to them. They go on to say that disk drive corruption happens once in every 67 terabytes of data processed.
Silent corruption can occur through a number of things, like failure of the media, background radiation and weaknesses in the data integrity. Silent corruption could potentially destroy a RAID as it gets worse over time.
The issues lies in the fact that while hard drives are growing in size, the error rates have remained constant. Modern hard drives aren’t that much better protected against silent corruption when compared to older drives. As drives increase in size, the chance of silent corruption occurring increases. Essentially, there’s more data to go wrong. Indeed, with a Network Appliance study claiming that 1 in 10 storage failures are due to silent corruption, chances are that it could happen to you.
So how do you prevent silent corruption from happening?
Sadly, there’s nothing you can really do, short of switching to a different storage medium like tape. But that’s hardly the most effective solution. Silent corruption occurs due to the way that hard drives are built and it could occur no matter how well you treat your drive. Instead, the question lies in how you can put layers of protection in place in order to ensure that you don’t lose your data if silent corruption does occur.
Iron Mountain suggests that you use erasure coding, which is a method for writing and protecting data that existed before RAIDs. This method fragments the original data and then stores it on different drives; two of these fragments can then be used to recreate the data, regardless of corruption.
Of course, it’s always advisable to have your data stored on a variety of mediums if possible. Each have their own advantages and disadvantages, but consider looking into things like external hard drives, RAID configurations or cloud storage. The wider you have your data spread then the more redundancy options you have available. However, there are problems with spreading your data, not least the time and cost factor associated with it.
You shouldn’t be worried about silent corruption, but you should certainly be aware that it exists. Just because your operating system or hard drive isn’t throwing up any errors doesn’t mean that your data is happily sitting on the drive unaffected. It could well be getting corrupted, all unbeknownst to you. Keep an eye on your data!


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