Hello, I'm create btrfs multi-device volume: (2TB * 5disks) 1. one device was converted from ext3, then delete sub-volume 'ext2'; 2. 'btrfs device add /dev/sd* /mnt/sdc1'; and some times again, Every disk adds by one, then move data from other disks. 2 times was running 'btrfs fi defrag -r -v -t 700K /mnt/sdc1; btrfs balance start /mnt/sdc1; btrfs scrub start /mnt/sdc1'. Finally I have FS at 5 devices. After, go to reboot pc, and I seen that 1 drive have no any partition. I'm full of sadness. I think that device was not correctly unmounted and one disk fail. mount -t btrfs -o degreded,ro,recovery,nospace_cache ... mount -t btrfs -o recovery,nospace_cache ... btrfs-find-root, btrfs-zero-log .. Finaly: btrfs restore -t 10404875644928 -v -i /dev/sda1 /mnt/uh1/eric/ - Success! but some directory is absent; 3.4 TB restored, but 4 (available disks)*1.82 Tb = 7.28 TB; and 7.28-3.4 = about 3.8 TB which is missing . Where is it ? How can i get it back? How can i try to restore more data? Please advice. _____ mount -t btrfs -o degraded,ro,recovery,nospace_cache /dev/sda1 /mnt/tmp3; dmesg | tail [11774.958996] BTRFS info (device sde1): allowing degraded mounts [11774.959001] BTRFS info (device sde1): enabling auto recovery [11774.959003] BTRFS info (device sde1): disabling disk space caching [11774.959955] BTRFS warning (device sde1): devid 5 missing [11774.986391] BTRFS: failed to read tree root on sde1 [11774.986408] BTRFS: failed to read tree root on sde1 [11774.986456] BTRFS: failed to read tree root on sde1 [11774.986473] BTRFS: failed to read tree root on sde1 [11774.986481] BTRFS: failed to read tree root on sde1 [11775.014471] BTRFS: open_ctree failed # btrfs-zero-log /dev/sda1 warning devid 5 not found already Check tree block failed, want=16845270495232, have=0 read block failed check_tree_block Couldn't read tree root ______ # uname -a Linux oit-875u 3.16.0-031600rc7-generic #201407271635 SMP Sun Jul 27 20:36:48 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux # btrfs fi show Label: none uuid: 841f1b5c-adb2-485f-a4cf-83bbf880dced Total devices 5 FS bytes used 9.09TiB devid 1 size 1.82TiB used 1.82TiB path /dev/sda1 devid 2 size 1.82TiB used 1.82TiB path /dev/sdc1 devid 3 size 1.82TiB used 1.82TiB path /dev/sdd1 devid 4 size 1.82TiB used 1.82TiB path /dev/sde1 *** Some devices missing Btrfs v3.14.1 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html