On 02/07/2012 11:39 AM, Ryan C. Underwood wrote: > Does anyone have any idea how I should proceed with the below quoted > situation? Unfortunately, I am going to have to give up on btrfs if > it is really so fragile. I am using kernel 3.2.2 and btrfs-tools > from November. > > On Sun, Feb 05, 2012 at 12:41:28PM -0600, Ryan C. Underwood wrote: >> Hi, >> >> I had a RAID5 double disk failure (40 megs or so bad sectors near >> middle of the second failed disk), bad news but I recovered what I was >> able to. >> >> The RAID contained a dm-crypt physical volume which then contained >> four logical volumes. Two are EXT4 and two BTRFS, about 1TB in size >> each. >> >> The failure occurred while the volumes were online and in use, so in >> addition to what was unreadable, all pending writes to the device >> between the failure and when the problem was discovered were lost as >> well. >>
Hi Ryan, So on the failure, what does dmesg show? checksum errors? >> The two ext4, fortunately, had some relatively minor corruption which >> was cleared up with a few rounds of fsck. The two btrfs are >> completely unhappy though and I do not know how to proceed, since >> btrfs problems are new to me. Any suggestions are welcome. >> btrfsck is not ready for data recovery, but only for error checking. But btrfs-tools do have some features that may help us, e.g zero-log. More recovery details refer to the thread from Hugo: http://www.spinics.net/lists/linux-btrfs/msg14890.html thanks, liubo >> Here is the basic picture of what is going on. >> >> # cat /etc/fstab >> # <file system> <mount point> <type> <options> <dump> <pass> >> #/dev/mapper/tr5ut-media /mnt/media btrfs >> defaults,compress=lzo,space_cache 0 2 >> >> /dev/mapper/tr5ut-media /mnt/media ext4 defaults 0 2 >> >> /dev/mapper/tr5ut-vicep--library /vicepa auto >> defaults,compress=lzo,space_cache 0 2 >> >> /dev/mapper/tr5ut-vicep--clones /vicepb auto >> defaults,compress=lzo,space_cache 0 2 >> >> >> You can see that btrfs device scan does not find anything, while >> btrfs-show finds one of the volumes and not the other. Fscking the >> found volume halts due to checksum and assertion errors, while fscking >> the other volume fails completely, I guess due to a missing >> 'superblock' type structure? >> >> >> seraph:~# btrfs device scan >> Scanning for Btrfs filesystems >> failed to read /dev/sr0 >> >> >> seraph:~# btrfs-show >> ** >> ** WARNING: this program is considered deprecated >> ** Please consider to switch to the btrfs utility >> ** >> failed to read /dev/sr0: No medium found >> Label: vicep-library uuid: 89b14d35-b31a-4fbe-a2d9-cb83cbcd3851 >> Total devices 1 FS bytes used 254.35GB >> devid 1 size 1.00TB used 299.04GB path /dev/dm-32 >> >> Btrfs Btrfs v0.19 >> >> >> seraph:~# btrfsck /dev/mapper/tr5ut-vicep--library >> checksum verify failed on 317874630656 wanted 8E19212D found FFFFFFA6 >> checksum verify failed on 317874630656 wanted 8E19212D found FFFFFFA6 >> checksum verify failed on 317874630656 wanted 491D9C1A found FFFFFFA6 >> checksum verify failed on 317874630656 wanted 8E19212D found FFFFFFA6 >> Csum didn't match >> btrfsck: root-tree.c:46: btrfs_find_last_root: Assertion >> `!(path->slots[0] == 0)' failed. >> Aborted >> >> >> seraph:~# btrfsck /dev/mapper/tr5ut-vicep--clones >> No valid Btrfs found on /dev/mapper/tr5ut-vicep--clones >> >> >> seraph:~# dpkg -l btrfs-tools >> Desired=Unknown/Install/Remove/Purge/Hold >> | >> Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend >> |/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad) >> ||/ Name Version >> Description >> +++-=============================================-=============================================-========================================================================================================== >> ii btrfs-tools 0.19+20111105-2 >> Checksumming Copy on Write Filesystem utilities >> >> >> -- >> Ryan C. Underwood, <neme...@icequake.net> >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in >> the body of a message to majord...@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
