Daniel Pocock posted on Sat, 23 Nov 2013 09:37:50 +0100 as excerpted:
> What about when btrfs detects a bad block checksum and recovers data
> from the equivalent block on another disk? The wiki says there will be
> a syslog event. Does btrfs keep any stats on the number of blocks that
> it considers unreliable and can this be queried from user space?
The way you phrased that question is strange to me (considers unreliable?
does that mean ones that it had to fix, or ones that it had to fix more
than once, or...), so I'm not sure this answers it, but from the btrfs
manpage...
>>>>
btrfs device stats [-z] {<path>|<device>}
Read and print the device IO stats for all devices of the filesystem
identified by <path> or for a single <device>.
Options
-z Reset stats to zero after reading them.
<<<<
Here's the output for my (dual device btrfs raid1) rootfs, here:
btrfs dev stat /
[/dev/sdc5].write_io_errs 0
[/dev/sdc5].read_io_errs 0
[/dev/sdc5].flush_io_errs 0
[/dev/sdc5].corruption_errs 0
[/dev/sdc5].generation_errs 0
[/dev/sda5].write_io_errs 0
[/dev/sda5].read_io_errs 0
[/dev/sda5].flush_io_errs 0
[/dev/sda5].corruption_errs 0
[/dev/sda5].generation_errs 0
As you can see, for multi-device filesystems it gives the stats per
component device. Any errors accumulate until a reset using -z, so you
can easily see if the numbers are increasing over time and by how much.
--
Duncan - List replies preferred. No HTML msgs.
"Every nonfree program has a lord, a master --
and if you use the program, he is your master." Richard Stallman
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
