On Wed, Feb 29, 2012 at 05:11:24PM -0600, Travis Shivers wrote:

Thank you all for helping. My btrfs array consists of 4 disks: 2 (2
TB) disks and 2(500 GB) disks. Since I have disks of different sizes,
I have the array being mirrored so that there are two copies of a file
on two separate disks. The data and metadata are mirrored.

I originally made the array by using this command:

# mkfs.btrfs -m raid1 -d raid1 /dev/sd[abcd]
(The drives were originally those letters)


All of the disks sit in an external 4 bay ESATA enclosure going into a
PCI-E RAID card set up as JBOD, so I can use btrfs' software
mirroring. This is the enclosure that I have:
http://www.newegg.com/Product/Product.aspx?Item=N82E16816132029

The corruption was unexpected. I am not entirely sure what caused it,
but a few days before the corruption, there were several power
outages. I do not think that the problem is with the actual hard drive
hardware since they are fairly new (6 months old) and they pass all
SMART tests. After a reboot, the btrfs array refused to mount and
started giving off errors. I do weekly scrubs, balances, and
defragmentation.

Ok, all of this should have worked.  Which kernel were you running when
you had the power outages?

I'm testing out the patch to skip the extent allocation tree at mount.
That will be the easiest way to get to the data (readonly, but it'll
work).

-chris