One of my hard disks is starting to have issues. I know this because I use ZFS. I run a weekly scrub and email myself the results. Every once in a while I see read failures coming from the USB hard disk. Recently, I started seeing checksum errors, however. If I were running a standard RAID 5, I would be suffering from "bit rot".
Jim Salter over at Ars Technica has a great article about bit rot and ZFS. At a high level, bit rot is when you attempt to write a 1 to a hard disk but the hard disk actually stores a 0. It could be a single occurrence, or it could be a sign of a dying hard disk. In my case, it might be a bad cable or enclosure. I have needed a new hard disk enclosure for a while, so I decided to buy a new enclosure and a new hard disk. I am going with a 4tb hard disk since I need more disk space.
What is important is I didn't lose any data for two reasons: ZFS (RAID-Z) checksums that data to identify where the bit-rot took place and ZFS tells me about a faulty hardware before it becomes a catastrophe.
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