HomeFiction #4: SSDs are always more reliable than HDDs
Fact #4: SandForce enables reliability that exceeds SSDs and leading enterprise HDDs
It is generally assumed that devices with moving parts are less reliable than those with all solid state components. It is also a fact that HDDs have moving parts that are highly susceptible to shock and vibration unlike SSDs. However there is more to reliability than just the parts that move. All electronic components do have a failure rate of some kind. If that failure rate is very low, then the device using that component has minimal risk of failure. On the other hand, if the device uses hundreds of components then the failure rates of each component is combined through a probability formula as a single failure rate.
SSDs are built using flash die that are assembled up to 8 die per package. For optimum capacity the SSD is assembled with up to 16 packages. That puts 128 individual die in one SSD. If the failure rate (unrecoverable read error) of one MLC die is conservatively 1,000 PPM (a failure probability of 0.1%) then using the probability formula for 128 devices the failure rate increases to 12.0% over the life of the SSD.
Using RAISE technology reduces the probability of a single unrecoverable read error by 100 times to 0.001%. Applying that same formula, the failure rate of the SSD drops from 12.0% to a mere 0.13%, nearly 100 times lower.
