I noticed one day that one of my HDDs had a write error rate (some tools call it multi zone error rate) of 3. Up until that day it had always showed 0. All the other S.M.A.R.T values were (and still are) flawless. After a couple of days, the write error rate changed back to 0.
I then remembered that about a week earlier, a power outage had caused the PC to shut down while it was transferring raw DV video footage from my camcorder to that same HDD. Do you think this could have caused the temporary rise in the error rate, or is the drive starting to lose its health? I know an error rate of 3 isn't really significant, I'm just interested.
I can pretty much confirm that the power outage did indeed cause the temporary increase in write error rate. There was another power failure and AGAIN it happened while the PC was writing a video file. This time I was playing a game and recording with FRAPS (about 40 MB/s). Some time later the write error rate was at 22, only to return to 0 again the next day.