Hard Disk Life Span
Hard disks usually give many years of trouble free operation, and from a data recovery perspective we see drives
from all points in history. Some over 20 years and some only a few months old. Recent averages show that the vast
majority of drives we receive are less than 3 years old. This does not necessarily mean that your 3 year old drive is about to
fail it just means that as it gets older it is more likely to expire.
Modern hard disks are built to a specification that meets a price factor set by their customers, so they design their products
within the price range. This can have an affect on life span as most manufacturers also have a 'professional' or 'enterprise' range of
drives that are two or three times the price of their standard range and have a longer warranty period. So it is fair to assume that
the higher priced products are of a better quality.
Prolonging the Life of Hard Disks
It has been suggested that there are a number of things that can be done to increase the life of a hard disk. But we are not sure that they work. Suggestions are;
- Hard disk defragmentation
The theory behind this seems perfectly logical - this is that when data on a hard disk becomes fragmented the hard disk works harder to access the data. Fragmentation occurs when for example you have software that maintains large data files. As the files grow in size they become fragmented. The first part of the file may be thousands of sectors apart from the second part and the third part, again thousands of sector apart and so on. When a read or write occurs the drive heads flick backwards and forwards reading the data putting strain on the moving parts of the head stack assembly. Defragmentation of these files reduces this wear and tear on the drive and so in theory should prolong the life of the drive.
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Power Cycling
Leaving a hard disk on prolongs its life. This seems logical, but not very environmentally friendly. Each time a hard disk spins up it places stress on the motor and it is during power up when it uses most power. The theory is that it is best to leave the hard disk on as long as possible to minimise the power strain on the motor and electronics. I would argue that the drives are designed to spin up and in fact spin ups are recorded in SMART logs and manufacturers have designed their drives to be power cycled more than 100,000 times. So will it help? Who knows, we have both here. We have RAID based servers here that are rarely powered off and are still running after 3 years with the same hard disks. We also have recovery machines that are power cycled several times a day that still have the original disks in them so the jury is still out on that one for us.
There are other 'physical' factors that can effect hard disk life.
- Heat
Heat can be a problem for hard disks, they are designed to run within a temperature range, typically 10 - 50 centigrade. In my opinion, the closer you can maintain this to room temperature, the better.
Hard disk are susceptible to heat as they use magnetism to store the data. Not like tape, but the data is stored as a magnetic flux pattern in the upper layers of the coatings on the platters. When magnets get hot, they lose their magnetism. The temperature required for this to happen is higher than the normal operating temperatures, but will have some if negligible effect on the coating. We use hard disk coolers on all out computers to minimise heat, the hard disks are also securely screwed to the computer cases to help dissipate latent heat. I'm not saying a warm hard disk is bad, just that it is better to avoid it where possible.
- Movement
However tempting it may be to move your running computer a few millimeters to align it with the edge of your desk, please resist the temptation. Moving a running hard disk can be a disaster. All it takes is for the heads to come into contact with the platters and the disk is dead. Also moving a laptop about especially if the HDD light is on is not recommended and it is safer to use them on a table rather than your lap. I have watched people on trains move them about whilst they are still working and I cringe every time.
We see more laptop based hard disks for recovery that we do any other type and most of them have head failures consistent with movement damage.