[Gluster-users] Bad sectors on brick

[Gandalf Corvotempesta]

2016-10-24 16:13 GMT+02:00 Niels de Vos <ndevos at redhat.com>:
> Yes, correct. But note that different filesystems can handle bad sectors
> differently, read-only filesystems is the most common default though.
>
> In 'man 8 mount' the option "errors=" describes the different values for
> ext2/3/4. Configuring it to "continue" will most likely cause data
> corruption or other bad problems and is definitely not advised ;-)

>From the opennebula forum:

"I think your notion of kernel behaviour during disk failures is not
correct. First of all, this is heavily filesystem dependent. Moreover,
when the bad sector is in the file data (as opposed to filesystem
metadata), read(2)returns something like ENXIO, and the filesystem
continues operating. When the bad sector is in the filesystem
metadata, most filesystems remount themselves read-only (AFAIK with
ext*fs, the exact behaviour can be set via tune2fs(8) as "remount
r/only", "panic", and "ignore" for the brave :-). When the disk is bad
to the point of generating unplug/replug sequence (e.g. SATA channel
reset), the filesystem starts returning ENXIO for all operations, but
it is still mounted. For systemd-based distributions, systemd
sometimes detects an unplugged disk (if it is mounted via /etc/fstab
entry), and umount(2)s it.

The kernel itself does not disable the disk, nor it remounts it r/only
in response to all types of failure."

so, how gluster handle a ENXIO ?