On Thu, 14 Feb 2013, Martin Steigerwald wrote:
Am Mittwoch, 13. Februar 2013 schrieb Fredrik Tolf:
You started the balance after above btrfs fi show command?
I did.
Then its obvious to me:
For some reason BTRFS is still trying to write to /dev/sdd, which isn´t
there anymore. That perfectly explains those lost page writes for me. If
that is the case, this seems to me like a serious bug in BTRFS.
Now I have disconnected the drive entirely, quite simply, so that I can
try to do simply what I should do if the drive really had failed
completely and I had gotten a replacement in its stead. Neither any sdd
nor any sdi is seen by the system anymore. However, I'm still getting
kernel messages about being unable to write to sdd:
Feb 15 04:37:41 nerv kernel: [252822.640560] lost page write due to I/O error
on /dev/sdd1
Feb 15 04:37:41 nerv kernel: [252822.644531] btrfs: bdev /dev/sdd1 errs: wr
362195, rd 26, flush 1, corrupt 0, gen 0
I can't say I know what conclusions that lead to with regards to your
observations.
I´d restart the machine, see that BTRFS is using both devices again and
then try the balance again.
I mentioned it in another mail, but I'd very much prefer not to do that.
I'd like to try and solve this as I normally should when a drive fails.
When I'm running btrfs fi show, this is what I'm getting now:
$ sudo ./btrfs fi show
Label: none uuid: 40d346bb-2c77-4a78-8803-1e441bf0aff7
Total devices 2 FS bytes used 2.66TB
devid 2 size 2.73TB used 2.67TB path /dev/sde1
*** Some devices missing
So that's what it should look like when a drive fails, right?
At this point, I'm trying to remove the missing device from the filesystem
as the Wiki indicates that I should be able to, but alas:
$ sudo ./btrfs device delete missing /mnt
ERROR: error removing the device 'missing' - Invalid argument
The dmesg tells me this:
Feb 15 04:42:22 nerv kernel: [253103.799201] btrfs: unable to go below two
devices on raid1
How do I remove the conception of the missing device so that I can replace
it? Should I simply add the replacement first, and only after that remove
the missing device?
If the latter, how can I "scratch" the previous btrfs metadata from this
"replacement" drive so that it doesn't try to autoreinsert it into the
filesystem when it is detected? I assume it won't be enough be just
zeroing the first few sectors of the drive, right?
Thanks for replying!
--
Fredrik Tolf
