I just wanted to share a small success story, partly for the archives.
I have an OpenBSD 6.5 amd64 server whose smartd has been whining about:
smartd: Device: /dev/sd0c, 1 Currently unreadable (pending) sectors
smartctl -a /dev/sd0c showed attribute 197 Current_Pending_Sector to be 1.
The disk is part of a softraid mirror sd2, so I offlined the disk
and rebuilt the mirror, thusly:
bioctl -O /dev/sd0a sd2
bioctl -R /dev/sd0a sd2
After a few hours of parity rebuild smartd has stopped spamming
/var/log/messages, and smartctl -a shows Current_Pending_Sector to be 0.
The parity rebuild, as expected, must have re-written the broken sector and
the disk reallocated the sector.
Sysadmin is happy!
Except that smartctl -a informs me that the disk predicts its power-on
lifetime to be 382 days, which apparently is not good. The other disk
in the mirror says nothing of this, so I have a very early warning
about getting a new disk... (sd0a's Reallocated_Sector_Ct is 148
while sd0b's is 0)