Your experience can be predicted by comparing "the mean time between failure" (MTBF) and the total hours you use your drive. Almost all hard drives have between 1%-10% failure rates and the results are so various and all over the place based on model, mfg, and the entity recording the data. Almost every hard drive study in existence finds different results- and the technology and actual specs of the models being produced change so frequently that it is very stupid to look at an old study on a drive that is no longer made and think it will directly translate to models currently being MFG today. There is nothing of value to be found in a white paper on HDD reliability that will help a consumer buy a model today.
Annualized failure rate:
Annualized failure rate (AFR) gives the estimated probability that a device or component will fail during a full year of use. It is a relation between the mean time between failure (MTBF) and the hours that a number of devices are run per year. AFR is estimated from a sample of like components — AFR and MTBF as given by vendors are population statistics that can not predict the behaviour of an individual unit.
For example, AFR is used to characterize the reliability of hard disk drives.
The relationship between AFR and MTBF is:
This equation assumes that the drives are powered on for the full 8760 hours of a year, and gives the estimated fraction of an original sample of drives that will suffer from disk failures, or, equivalently, 1 − AFR is the fraction of drives that will show no failures over a year. It is based on an exponential failure distribution (see Failure rate for a full derivation).
This can be approximated by, assuming a small AFR,
(expressed in %)
For example, a common specification for PATA and SATA drives may be 300,000 MTBF, giving a theoretical 2.88% annualized failure rate i.e. a 2.88% chance that a given drive will fail during a year of use.
The AFR for a drive is derived from time-to-fail data from a reliability-demonstration test (RDT).
Note that annualized failure rate will increase towards and beyond the end of the service life of a device or component. Google's 2007 study found, based on a large field sample of drives, that actual AFRs for individual drives ranged from 1.7% for first year drives to over 8.6% for three-year old drives. A CMU 2007 study showed an estimated 3% mean AFR over 1–5 years based on replacement logs for a large sample of drives.link
That's probably one of the better white papers on HDD reliability^
But like I said- it's all totally crap today. Studying reliability of models no longer for sale or being produced has no translation to a purchase decision today. White papers are useless to a consumer. A hard drive is a hard drive. They are all about the same and they all fail at some point.If you compare the MTBF of a 10,000rpm WD hard drive today ( 1.4 million hours ) to a 5400rpm drive ( 300,000) it's pretty obvious which is going to last longer
A WD black is rated at 1,000,000 and a Blue is 600,000. Last time I saw a Green rated was 300,000 but then WD stopped rating them. That is the old data and ratings I remember. When 5400rpm Intellipower drives started coming out and failing at an increasing rate WD made the move to stop publishing MTBF rates for 5400rpm drives and only does so on the 10k and 7200 drives because the data and ratings for 5400rpm drives are generally poor.
I find it funny they stopped rating MTBF for the GREEN 5400rpm.. etc.. But still provide the ratings for 7200rpm and 10,000rpm Enterprise level drives in product brochures:
You have to dig into the spec sheet to find any data at all on this subject:
And^ You only find a rating for 300,000 load and unload cycles.. with no MTBF data at all.
I have seen some specs for the WD RED that suggest 1,000,000 MTBF and if I had to guess I'd say the RED is more durable than the GREEN drives- but both are less durable statistically than a faster Raptor 10,000rpm Hard drive from the same MFG. The Audio Video drives, and the Enterprise drives @ 7200rpm are rated as much as 2 million MTBF suggesting they are also more reliable than 5400rpm drives. The idea a slower spindle speed drive lasts longer is just BS. There are many factors that determine reliability other than spindle speed. The reason the faster drives are more reliable is not because they spin faster- but because they are build and designed better. The reason why 5400rpm are among the worst reliability today is because they are designed to be affordable, quiet and cool- and not at all designed to be durable in a demanding environment and heavy use.Edited by Mfusick - 6/16/13 at 8:41am