can't mount RAID-1 btrfs after reboot

can't mount RAID-1 btrfs after reboot

[Tomasz Chmielewski]

I can't mount RAID-1 btrfs after reboot (well, sort of).

Using 2.6.31-rc5 and btrfs-progs 0.19, I created a RAID-1 fileystem 
using these command line options:

# mkfs.btrfs -L btrfs-data -m raid1 -d raid1 /dev/sda4 /dev/sdb4


After which I was able to mount the filesystem with either of the below 
(or both):

# mount /dev/sda4 /mnt/btrfs-sda4

# mount /dev/sdb4 /mnt/btrfs-sdb4


After a reboot, I'm no longer able to mount the filesystem from /dev/sda4:

# mount /dev/sda4 /mnt/btrfs/

Mount command complains and doesn't mount it and says I can find more 
info in dmesg:

Btrfs loaded
device label btrfs-data devid 1 transid 67 /dev/sda4
btrfs: failed to read the system array on sda4
btrfs: open_ctree failed


I'm able to mount the filesystem by using /dev/sdb4:

# mount /dev/sdb4 /mnt/btrfs/

After which I can unmount it, and use /dev/sda4 to mount the filesystem:

# umount /dev/sdb4
# mount /dev/sda4 /mnt/btrfs/


Does it make sense?

It behaved like this also with some earlier kernels.


-- 
Tomasz Chmielewski
http://wpkg.org

Re: can't mount RAID-1 btrfs after reboot

[Jens Axboe]

On Fri, Aug 14 2009, Tomasz Chmielewski wrote:
> I can't mount RAID-1 btrfs after reboot (well, sort of).
>
> Using 2.6.31-rc5 and btrfs-progs 0.19, I created a RAID-1 fileystem  
> using these command line options:
>
> # mkfs.btrfs -L btrfs-data -m raid1 -d raid1 /dev/sda4 /dev/sdb4
>
>
> After which I was able to mount the filesystem with either of the below  
> (or both):
>
> # mount /dev/sda4 /mnt/btrfs-sda4
>
> # mount /dev/sdb4 /mnt/btrfs-sdb4
>
>
> After a reboot, I'm no longer able to mount the filesystem from /dev/sda4:
>
> # mount /dev/sda4 /mnt/btrfs/
>
> Mount command complains and doesn't mount it and says I can find more  
> info in dmesg:
>
> Btrfs loaded
> device label btrfs-data devid 1 transid 67 /dev/sda4
> btrfs: failed to read the system array on sda4
> btrfs: open_ctree failed
>
>
> I'm able to mount the filesystem by using /dev/sdb4:
>
> # mount /dev/sdb4 /mnt/btrfs/
>
> After which I can unmount it, and use /dev/sda4 to mount the filesystem:
>
> # umount /dev/sdb4
> # mount /dev/sda4 /mnt/btrfs/

Try btrfsctl -a first.

-- 
Jens Axboe

Re: can't mount RAID-1 btrfs after reboot

[Tomasz Chmielewski]

Jens Axboe wrote:

>> I'm able to mount the filesystem by using /dev/sdb4:
>>
>> # mount /dev/sdb4 /mnt/btrfs/
>>
>> After which I can unmount it, and use /dev/sda4 to mount the filesystem:
>>
>> # umount /dev/sdb4
>> # mount /dev/sda4 /mnt/btrfs/
> 
> Try btrfsctl -a first.

It seems to do the trick.

I suppose longer term, doing "btrfsctl -a" before mounting a (RAID) 
btrfs filesystem shouldn't be needed, or?


-- 
Tomasz Chmielewski
http://wpkg.org

Re: can't mount RAID-1 btrfs after reboot

[Calvin Walton]

On Mon, 2009-08-31 at 01:09 +0200, Tomasz Chmielewski wrote:
> Jens Axboe wrote:
> 
> >> I'm able to mount the filesystem by using /dev/sdb4:
> >>
> >> # mount /dev/sdb4 /mnt/btrfs/
> >>
> >> After which I can unmount it, and use /dev/sda4 to mount the filesystem:
> >>
> >> # umount /dev/sdb4
> >> # mount /dev/sda4 /mnt/btrfs/
> > 
> > Try btrfsctl -a first.
> 
> It seems to do the trick.
> 
> I suppose longer term, doing "btrfsctl -a" before mounting a (RAID) 
> btrfs filesystem shouldn't be needed, or?

Shorter term, writing a udev rule along the lines of

ENV{ID_FS_TYPE}=="btrfs", RUN+="/sbin/btrfsctl -A %N"

(put it in /etc/udev/rules.d/64-btrfs-scan.rules or so) will cause your
btrfs to be scanned when found. Possibly something like this could be
distributed with btrfsprogs?

-- 
Calvin Walton <calvin.walton@gmail.com>