This patch series adds support for replacing disks at runtime. It replaces the following steps in case a disk was lost: mount ... -o degraded btrfs device add new_disk btrfs device delete missing
Or in case a disk just needs to be replaced because the error rate is increasing: btrfs device add new_disk btrfs device delete old_disk Instead just run: btrfs replace mountpoint old_disk new_disk The device replace operation takes place at runtime on a live filesystem, you don't need to unmount it or stop active tasks. It is safe to crash or lose power during the operation, the process resumes with the next mount. The copy usually takes place at 90% of the available platter speed if no additional disk I/O is ongoing during the copy operation, thus the degraded state without redundancy can be left quickly. The copy process is started manually. It is a different project to react on an increased device I/O error rate with an automatic start of this procedure. The patch series is based on btrfs-next and also available here: git://btrfs.giantdisaster.de/git/btrfs device-replace The user mode part is the top commit of git://btrfs.giantdisaster.de/git/btrfs-progs master replace start [-Bfr] <path> <srcdev>|<devid> <targetdev> Replace device of a btrfs filesystem. On a live filesystem, duplicate the data to the target device which is currently stored on the source device. If the source device is not avail- able anymore, or if the -r option is set, the data is built only using the RAID redundancy mechanisms. After completion of the operation, the source device is removed from the filesystem. If the srcdev is a numerical value, it is assumed to be the device id of the filesystem which is mounted at mount_point, otherwise is is the path to the source device. If the source device is disconnected, from the system, you have to use the devid parame- ter format. The targetdev needs to be same size or larger than the srcdev. Options -r only read from srcdev if no other zero-defect mirror exists (enable this if your drive has lots of read errors, the access would be very slow) -f force using and overwriting targetdev even if it looks like containing a valid btrfs filesystem. A valid filesystem is assumed if a btrfs superblock is found which contains a correct checksum. Devices which are cur- rently mounted are never allowed to be used as the tar- getdev -B do not background replace status [-1] <path> Print status and progress information of a running device replace operation. Options -1 print once instead of print continously until the replace operation finishes (or is canceled) replace cancel <path> Cancel a running device replace operation. Stefan Behrens (26): Btrfs: rename the scrub context structure Btrfs: remove the block device pointer from the scrub context struct Btrfs: make the scrub page array dynamically allocated Btrfs: in scrub repair code, optimize the reading of mirrors Btrfs: in scrub repair code, simplify alloc error handling Btrfs: cleanup scrub bio and worker wait code Btrfs: add two more find_device() methods Btrfs: Pass fs_info to btrfs_num_copies() instead of mapping_tree Btrfs: pass fs_info to btrfs_map_block() instead of mapping_tree Btrfs: add btrfs_scratch_superblock() function Btrfs: pass fs_info instead of root Btrfs: avoid risk of a deadlock in btrfs_handle_error Btrfs: enhance btrfs structures for device replace support Btrfs: introduce a btrfs_dev_replace_item type Btrfs: add a new source file with device replace code Btrfs: disallow mutually exclusiv admin operations from user mode Btrfs: disallow some operations on the device replace target device Btrfs: handle errors from btrfs_map_bio() everywhere Btrfs: add code to scrub to copy read data to another disk Btrfs: change core code of btrfs to support the device replace operations Btrfs: introduce GET_READ_MIRRORS functionality for btrfs_map_block() Btrfs: changes to live filesystem are also written to replacement disk Btrfs: optionally avoid reads from device replace source drive Btrfs: increase BTRFS_MAX_MIRRORS by one for dev replace Btrfs: allow repair code to include target disk when searching mirrors Btrfs: add support for device replace ioctls fs/btrfs/Makefile | 2 +- fs/btrfs/check-integrity.c | 29 +- fs/btrfs/compression.c | 6 +- fs/btrfs/ctree.h | 127 ++- fs/btrfs/dev-replace.c | 843 ++++++++++++++++++++ fs/btrfs/dev-replace.h | 44 ++ fs/btrfs/disk-io.c | 79 +- fs/btrfs/extent-tree.c | 5 +- fs/btrfs/extent_io.c | 28 +- fs/btrfs/extent_io.h | 4 +- fs/btrfs/inode.c | 39 +- fs/btrfs/ioctl.c | 117 ++- fs/btrfs/ioctl.h | 45 ++ fs/btrfs/print-tree.c | 3 + fs/btrfs/reada.c | 31 +- fs/btrfs/scrub.c | 1822 ++++++++++++++++++++++++++++++++------------ fs/btrfs/super.c | 30 +- fs/btrfs/transaction.c | 7 +- fs/btrfs/volumes.c | 624 +++++++++++++-- fs/btrfs/volumes.h | 26 +- 20 files changed, 3244 insertions(+), 667 deletions(-) create mode 100644 fs/btrfs/dev-replace.c create mode 100644 fs/btrfs/dev-replace.h -- 1.8.0 -- 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