I haven't experienced ANY drive failures. Which means I'm probably on track for one soon...
When I started out, I began with a single 5-disk vdev using a SATA port multiplier enclosure to connect the drives. Over time, I bought more SATA port multipliers, but eventually ran into tons of problems with the SATA PM technology. I do not recommend anyone use SATA PM for anything that really matters, and if you must use it, do not run more than one port multiplier on a single system at a time. So, I had tons of failures where the drives would just drop out due to their enclosure, at least once a month.
After switching to SAS and SAS expanders for drive connectivity, about a year ago, I have had NO problems at all. Rock solid.
Edit: I think I've lucked out by choosing very good, slow, low-temperature drives, first the HD204UI by Samsung, then the WD Red series. With my air conditioning, and the airflow in my rack, the drives average around 32 degrees C (a little colder than Google's report would suggest is best, but close). I would get very anxious if I were running with faster/hotter drives, or "green" drives not designed for 24/7 use.
Thanks. I've got a number of WD Red series drives too, though my rack seems to run a fair bit hotter than yours. (37 degrees C). No failures in a year so fingers crossed.
When I started out, I began with a single 5-disk vdev using a SATA port multiplier enclosure to connect the drives. Over time, I bought more SATA port multipliers, but eventually ran into tons of problems with the SATA PM technology. I do not recommend anyone use SATA PM for anything that really matters, and if you must use it, do not run more than one port multiplier on a single system at a time. So, I had tons of failures where the drives would just drop out due to their enclosure, at least once a month.
After switching to SAS and SAS expanders for drive connectivity, about a year ago, I have had NO problems at all. Rock solid.
Edit: I think I've lucked out by choosing very good, slow, low-temperature drives, first the HD204UI by Samsung, then the WD Red series. With my air conditioning, and the airflow in my rack, the drives average around 32 degrees C (a little colder than Google's report would suggest is best, but close). I would get very anxious if I were running with faster/hotter drives, or "green" drives not designed for 24/7 use.