I have seen separate answers for all the little pieces of my question, I looked really hard, but it still doesn't seem to make any sense. A little history of how this happened.Yesterday by using randomly using ls in my root directory as root, I discover a file called dead.letter.Said file contains warnings that seem pretty ominous:Device: /dev/sda [SAT], 8 Currently unreadable (pending) sectorsDevice: /dev/sda [SAT], 8 Offline uncorrectable sectorsThose two warnings repeat for a final file size of 53346 (bytes, I guess? This is what the ls command said).I check online, search engines inform me that my hard drive is dying. OK, good, I know what's going on.Except that I checked my hard drive's health two weeks ago and it was fine, and when I check it now through smartctl -H /dev/sda it tells me overall health is good.Even weirder, why is it in a dead.letter file? From what I understand it's a file that happens when you abort a mail you're currently writing, so wtf?The dead.letter file, says the stat command, has not been modified since January 18th. Was this a one-time event?So here's my question: is my hard drive fine or is it dying in a really sneaky way? I have no idea what's going on.I run a Fedora 24/Gnome Shell on a 2012 Asus U36SG. Filesystem is all ext4 on LVM2 I think. I hope this is enough information!
dead.letter file warns me about uncorrectable sectors I can't find
command line;fedora;logs;hard disk
The dead.letter file is created by mail clients when they cannot send email. It's likely you don't have any mail subsystem installed on your machine. The date of the file corresponds to the date the mail was attempted.On 18th January it looks like smartctl tried to warn you of 8 sectors that couldn't be read. This is a warning sign that the disk may be dying but it's not a definite marker. I'd start saving for a replacement, though.You confirmed that the disk has been more recently checked and was reported to be fine. What's happened here is that you wrote new data to those sectors, the disk failed to write them, and silently remapped them to dedicated spare sectors elsewhere on the disk.Three are now no outstanding faulty sectors.As the disk gets older and more sectors need remapping, eventually the spares will get filled up and real data will be lost. It's just a matter of time. Ensure you have got backups - or that you can afford to lose any or all of your data either in one big go out subtly so you don't really notice the corruption at first.