Martin,
below patch will help to obtain the device list from the kernel.
https://patchwork.kernel.org/patch/4996111/
(just fyi above patch is v1 which should apply,
however its v2 would not apply without sysfs patches)
However other data what we need is group profile,
collect them when and if device could mount.
(was there any patch which can obtain the group profile,
without mounting ?, I vaguely remember some efforts/comment
on that before).
Thanks, Anand
On 06/15/2015 02:24 AM, Martin wrote:
Do you know, where I can find this kernel-patch because I didn't find it. Then
I will build the patched kernel and send the devlist-output.
Thanks, Martin
Am Freitag, 12. Juni 2015, 18:38:18 schrieb Anand Jain:
On 06/11/2015 09:03 PM, Martin wrote:
It is reproduceable but the logs doesn't say much:
dmesg:
[151183.214355] BTRFS info (device sdb2): allowing degraded mounts
[151183.214361] BTRFS info (device sdb2): disk space caching is enabled
[151183.317719] BTRFS: bdev (null) errs: wr 7988389, rd 7707002, flush
150,
corrupt 0, gen 0
[151214.513046] BTRFS: too many missing devices, writeable mount is not
allowed
presumably (we did not confirm that only one disk is missing from
kernel point of view?) with One disk missing if you are still getting
this that means, there is a group profile in your disk pool that does
not tolerate single disk failure either.
So now how would we check all the group profiles in an unmount(able)
state ?
There is a patch to show devlist using /proc/fs/btrfs/devlist.
That would have helped here to debug. I am ok if you could confirm
that using any other method as well.
Thanks, Anand
[151214.548566] BTRFS: open_ctree failed
Can I get more info out of the kernel-module?
Thanks, Martin
Am Donnerstag, 11. Juni 2015, 08:04:04 schrieb Anand Jain:
On 10 Jun 2015, at 5:35 pm, Martin <develop@xxxxxxxxxx> wrote:
Hello Anand,
the failed disk was removed. My procedure was the following:
- I found some write errors in the kernel log, so
- I shutdown the system
- I removed the failed disk
- I powered on the system
- I mounted the remaining disk degraded,rw (works OK)
- the system works an and was rebooted some times, mounting degraded,rw
works - suddentlym mounting degraded,rw stops working and only
degraded,ro works.
any logs to say why. ?
Or
If these (above) stages are reproducible, could you fetch them afresh?
Thanks Anand
Thanks, Martin
Am Mittwoch, 10. Juni 2015, 15:46:52 schrieb Anand Jain:
On 06/10/2015 02:58 PM, Martin wrote:
Hello Anand,
the
mount -o degraded <good-disk> <-- this should work
is my problem. The fist times it works but suddently, after a reboot,
it
fails with message "BTRFS: too many missing devices, writeable mount
is
not allowed" in kernel log.
the failed(ing) disk is it still physically in the system ?
when btrfs finds EIO on the intermittently failing disk,
ro-mode kicks in, (there are some opportunity for fixes which
I am trying). To recover, the approach is to make the failing
disk a missing disk instead, by pulling out the failing disk
from the system and boot. When system finds disk missing
(not EIO rather) it should mount rw,degraded (from the VM part
at least) and then replace (with a new disk) should work.
Thanks, Anand
"btrfs fi show /backup2" shows:
Label: none uuid: 6d755db5-f8bb-494e-9bdc-cf524ff99512
Total devices 2 FS bytes used 3.50TiB
devid 4 size 7.19TiB used 4.02TiB path /dev/sdb2
*** Some devices missing
I suppose there is a "marker", telling the system only to mount in
ro-mode?
Due to the ro-mount I can't replace the missing one because all the
btrfs-
commands need rw-access ...
Martin
Am Mittwoch, 10. Juni 2015, 14:38:38 schrieb Anand Jain:
Ah thanks David. So its 2 disks RAID1.
Martin,
disk pool error handle is primitive as of now. readonly is the
only
action it would take. rest of recovery action is manual. thats
unacceptable in a data center solutions. I don't recommend btrfs
VM
productions yet. But we are working to get that to a complete VM.
For now, for your pool recovery: pls try this.
- After reboot.
- modunload and modload (so that kernel devlist is empty)
- mount -o degraded <good-disk> <-- this should work.
- btrfs fi show -m <-- Should show missing if you don't let me
know.
- Do a replace of the missing disk without reading the source
disk.
Good luck.
Thanks, Anand
On 06/10/2015 11:58 AM, Duncan wrote:
Anand Jain posted on Wed, 10 Jun 2015 09:19:37 +0800 as excerpted:
On 06/09/2015 01:10 AM, Martin wrote:
Hello!
I have a raid1-btrfs-system (Kernel 3.19.0-18-generic, Ubuntu
Vivid
Vervet, btrfs-tools 3.17-1.1). One disk failed some days ago. I
could
remount the remaining one with "-o degraded". After one day and
some
write-operations (with no errrors) I had to reboot the system. And
now
I can not mount "rw" anymore, only "-o degraded,ro" is possible.
In the kernel log I found BTRFS: too many missing devices,
writeable
mount is not allowed.
I read about https://bugzilla.kernel.org/show_bug.cgi?id=60594 but
I
did no conversion to a single drive.
How can I mount the disk "rw" to remove the "missing" drive and
add
a
new one?
Because there are many snapshots of the filesystem, copying the
system
would be only the last alternative ;-)
How many disks you had in the RAID1. How many are failed ?
The answer is (a bit indirectly) in what you quoted. Repeating:
One disk failed[.] I could remount the remaining one[.]
So it was a two-device raid1, one failed device, one remaining,
unfailed.
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