Hallo, linux-btrfs, I've (once again) tried "add" and "delete".
First, with 3 devices (partitions): mkfs.btrfs -d raid0 -m raid1 /dev/sdk1 /dev/sdl1 /dev/sdm1 Mounted (to /mnt/btr), filled with about 100 GByte data. Then btrfs device add /dev/sdj1 /mnt/btr results in # show Label: none uuid: 6bd7d4df-e133-47d1-9b19-3c7565428770 Total devices 4 FS bytes used 100.44GB devid 3 size 68.37GB used 44.95GB path /dev/sdm1 devid 2 size 136.73GB used 43.95GB path /dev/sdl1 devid 1 size 16.96GB used 16.96GB path /dev/sdk1 devid 4 size 136.73GB used 0.00 path /dev/sdj1 Btrfs Btrfs v0.19 # df Data, RAID0: total=103.81GB, used=100.30GB Data: total=8.00MB, used=0.00 System, RAID1: total=8.00MB, used=12.00KB System: total=4.00MB, used=0.00 Metadata, RAID1: total=1.00GB, used=136.29MB Metadata: total=8.00MB, used=0.00 --------------------------------------------- # Then mkfs filesystem balance /mnt/btr # show Label: none uuid: 6bd7d4df-e133-47d1-9b19-3c7565428770 Total devices 4 FS bytes used 100.44GB devid 3 size 68.37GB used 42.94GB path /dev/sdm1 devid 2 size 136.73GB used 43.20GB path /dev/sdl1 devid 1 size 16.96GB used 16.94GB path /dev/sdk1 devid 4 size 136.73GB used 2.20GB path /dev/sdj1 Btrfs Btrfs v0.19 # df Data, RAID0: total=104.75GB, used=100.30GB System, RAID1: total=8.00MB, used=12.00KB System: total=4.00MB, used=0.00 Metadata, RAID1: total=256.00MB, used=136.23MB --------------------------------------------- ######################### Next step: btrfs device delete /dev/sdk1 /mnt/btr # show Label: none uuid: 6bd7d4df-e133-47d1-9b19-3c7565428770 Total devices 4 FS bytes used 100.43GB devid 3 size 68.37GB used 43.00GB path /dev/sdm1 devid 2 size 136.73GB used 43.26GB path /dev/sdl1 devid 4 size 136.73GB used 17.26GB path /dev/sdj1 *** Some devices missing Btrfs Btrfs v0.19 # df Data, RAID0: total=103.00GB, used=100.30GB System, RAID1: total=8.00MB, used=12.00KB Metadata, RAID1: total=256.00MB, used=131.62MB --------------------------------------------------------- All commands seemed to work well, without any error message. "blkid" showed the expected data, especially blkid /dev/sdk1 shows nothing - the partitions seems to be really empty. Unmounted, mounted again: # show Btrfs Btrfs v0.19 # df Data: total=8.00MB, used=64.00KB System, DUP: total=8.00MB, used=4.00KB System: total=4.00MB, used=0.00 Metadata, DUP: total=1.00GB, used=24.00KB Metadata: total=8.00MB, used=0.00 ------------------------------------------------ "show" doesn't show any part of the bundle of 3 partitions. That's more than I've expected from the option "delete" ... ------------------------------------------------- Famous last words from "dmesg": device fsid 6bd7d4df-e133-47d1-9b19-3c7565428770 devid 3 transid 437 /dev/sdm1 device fsid 6bd7d4df-e133-47d1-9b19-3c7565428770 devid 2 transid 437 /dev/sdl1 device fsid 6bd7d4df-e133-47d1-9b19-3c7565428770 devid 4 transid 437 /dev/sdj1 device label SCSI devid 1 transid 7 /dev/sdj1 btrfs: disk space caching is enabled device label SCSI devid 1 transid 10 /dev/sdj1 btrfs: disk space caching is enabled device label SCSI devid 1 transid 13 /dev/sdj1 btrfs: disk space caching is enabled device fsid 6bd7d4df-e133-47d1-9b19-3c7565428770 devid 3 transid 437 /dev/sdm1 btrfs: disk space caching is enabled btrfs: failed to read chunk tree on sdm1 btrfs: open_ctree failed device fsid 6bd7d4df-e133-47d1-9b19-3c7565428770 devid 2 transid 437 /dev/sdl1 btrfs: disk space caching is enabled btrfs: failed to read chunk tree on sdm1 btrfs: open_ctree failed device label SCSI devid 1 transid 16 /dev/sdj1 btrfs: disk space caching is enabled end_request: I/O error, dev fd0, sector 0 end_request: I/O error, dev fd0, sector 0 -------------------------- My "dmesg" doesn't write time stamps, there may be some lines from previous tests. --------------------------- Kernel 3.2.5 (self made), btrfs from darksatanic.net, "bztfs-progs- unstable". Viele Gruesse! Helmut -- 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