My personal desktop system at home has 5 SATA drives racked up inside. Recently my system started failing in odd ways like random kernel panics and I eventually traced it to random degrades on the RAID array. Sometimes I could boot, other times I couldn't and so on. After chasing software issues for a while I finally went to pull the drives and discovered the real reason they were failing: they were hotter than a barbecue on the 4th of July! The front case fan had seized up and the PS fan had a loose power connector caught in its grate so the inside of the case had been cooking.
As a hold over, I found a house fan and got that sucker cooled off. It ran great with everything nice an chill. About this time I learned how to get drive temperature readings from S.M.A.R.T.
for i in a b c d e; do sudo smartctl --all /dev/sd$i | grep Temperature_Celsius done
Now I know that with my case opened an a house fan permanently cleaning out the cobwebs the drives run at 31-32°. A quick test with no ventilation to replicate the failed state shows the drives ran up to the high 40s pretty quickly. I don't know how bad it was during the actual failure or how long its been like that.
With this in mind I replaced the failing fans, added a couple more, upgraded the front one blowing across the drives from 80mm to 120mm and closed it back up. With it standing back upright again the temp range is now generally sitting at 32° on the bottom of the set and 37° at the top.
What is a general safe operating temperature range for SATA drives? Should 37° be a concern or is drive damage not an issue until after a certain point?
Although the drives seem to test out fine now, how likely is past exposure to heat likely to make them prone to failure now?