Hard Drive Reliability

One useful measure of reliability is provided by Blackblaze a Data Centre operator. They are faily unique in that they publish their Hard Drive failure rates. With (as at Sept 2018) some 99,636 drives, using the ones that are most reliable is clearly very important to their business. However, before we get into the stats, it is important to note that Data Centres, like Backblaze,  do tend to use the larger capacity drives and ones designed for professional IT data Centre use. Their drives are also held in what are ideal conditions to maintain the maximum reliability and clearly they don't get subjected to shocks that you would get in e.g. a laptop being dropped. They can thus, be expected to be more reliable in use than your typical laptop Hard Drive. So, this said, their latest overall lifetime failure rate is 1.71% (their best ever failure rate). This means that, over a five year period they expect just less than 1 in 50 of their Hard Drives to fail.   The evidence also suggests that over time drives have been getting ever so slightly more reliable - as a general trend. 

For a typical laptop or PC user, or someone using an external Hard Drive.  We would suggest the odds of a failure will be higher than the 1 in 50 suggested above. Another factor to consider, is that there is evidence that failure rates can increase over time.  What this means is that the longer you use a drive the greater the tendency for it to fail. A good analogy is, it's a bit like running a car. You can get problems in the first few years. But the longer you keep it the more prone it will be to breaking down. Sadly, unlike a car, Hard Drives can only vary rarely be repaired. Fortunately, they most likely can have their data recovered and out Lab technicians have been successful in getting data back with even very damaged drives.

So, where does this leave us? The point of this post is not to put you off Hard Drives.  For large data storage they are still be the most cost effective and practical means of storage. There is a general trend towards SSD's. We plan to do a post on them at a  later date.  However, we are seeing quite a few SSD failures in the Lab too. As they become more popular there is more information available on their reliability performance.  However they are not 100% reliable and they do fail too, especially over time.