Trying: btrfs device delete missing /
appears not to do anything for a "/" mount for where I have swapped out a HDD: # btrfs filesystem show Label: 'test_btrfs_misc_5' uuid: 7d29d4e6-efdc-41dc-9aa8-e74dfbe13cc9 Total devices 2 FS bytes used 28.00KB devid 1 size 59.74GB used 2.03GB path /dev/sdd5 *** Some devices missing Label: 'test_btrfs_root_4' uuid: 269e142c-e561-4227-b2b0-fe2f9fb99391 Total devices 3 FS bytes used 10.55GB devid 4 size 56.00GB used 12.03GB path /dev/sde4 devid 1 size 56.00GB used 12.05GB path /dev/sdd4 *** Some devices missing Btrfs v0.20-rc1-358-g194aa4a # btrfs device delete missing / # btrfs filesystem show Label: 'test_btrfs_misc_5' uuid: 7d29d4e6-efdc-41dc-9aa8-e74dfbe13cc9 Total devices 2 FS bytes used 28.00KB devid 1 size 59.74GB used 2.03GB path /dev/sdd5 *** Some devices missing Label: 'test_btrfs_root_4' uuid: 269e142c-e561-4227-b2b0-fe2f9fb99391 Total devices 3 FS bytes used 10.55GB devid 4 size 56.00GB used 12.03GB path /dev/sde4 devid 1 size 56.00GB used 12.05GB path /dev/sdd4 *** Some devices missing Btrfs v0.20-rc1-358-g194aa4a All on the latest "Linux 3.11.5-gentoo". # df -h | egrep '/$' rootfs 112G 22G 89G 20% / /dev/sdd4 112G 22G 89G 20% / Aside: Adding the /dev/sde4 device caused no balance action until I deleted a device to reduce the raid1 mirror (data and metadata) down to the two devices. The "missing" device was an old HDD that had physically failed. No data was lost for that example failure. Hope of interest, Martin -- 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