I've been using btrfs for a couple of years now and it has saved my ass on a couple of occasions - this weekend again.
I'm periodically doing a
btrfs scrub
on all hard drives. What btrfs scrub does: It validates all checkssums on the given filesystem, so you can see if one (or more than one) file have succumbd to
bit rot. Guess what?
scrub device /dev/mapper/crbackup (id 1) history
Scrub started: Sat Feb 1 00:00:09 2020
Status: finished
Duration: 5:20:51
Total to scrub: 1.63TiB
Rate: 75.15MiB/s
Error summary: csum=256
Corrected: 0
Uncorrectable: 256
Unverified: 0
Fortunately the files in question are rather unimportant backups:
[1061203.625001] BTRFS warning (device dm-3): checksum error at logical 22266249216 on dev /dev/mapper/crbackup, physical 23348379648, root 14466, inode 6257873, offset 71372800, length 4096, links 1 (path: var/log/journal/ea31f7c7a00d9c85d020e2475ba79427/system@205f60a021bb49848e1bfd0d90a5b20b-000000000093d480-000590ce96ca6d78.journal)
If I'd sill using old-fashioned filesystems like ext4 I wouldn't have noticed :-)
#
btrfs #
linux