But not for the reasons you'd think -- mechanically they're incredibly reliable these days, even when violence is done to them.
What sucks now is the software running on the embedded drive controller, especially on the most recent highest-capacity drives available at any one time -- the most common bug is for the whole drive to just stop responding for several seconds.
There is still one type of hardware error causing problems -- single-bit corruption errors. They're much less likely than they used to be, and the drive will catch them with a checksum when read back, but capacities are so high that the probability of hitting one when reading back a full drive is nearly %100. This makes RAID-5 and other parity-based striping systems almost completely unviable these days -- you'll never be able to rebuild the array from n-1 drives without hitting a single-bit error. And because of the software bugs in drives, they drop out for no reason all the time forcing you to rebuild the array (which then fails because a cosmic ray caused a single-bit error).
SSDs won't save you either, they have even more classes of software bugs present in their embedded controllers.
What sucks now is the software running on the embedded drive controller, especially on the most recent highest-capacity drives available at any one time -- the most common bug is for the whole drive to just stop responding for several seconds.
There is still one type of hardware error causing problems -- single-bit corruption errors. They're much less likely than they used to be, and the drive will catch them with a checksum when read back, but capacities are so high that the probability of hitting one when reading back a full drive is nearly %100. This makes RAID-5 and other parity-based striping systems almost completely unviable these days -- you'll never be able to rebuild the array from n-1 drives without hitting a single-bit error. And because of the software bugs in drives, they drop out for no reason all the time forcing you to rebuild the array (which then fails because a cosmic ray caused a single-bit error).
SSDs won't save you either, they have even more classes of software bugs present in their embedded controllers.