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Diffstat (limited to 'Documentation/btrfs-device.asciidoc')
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diff --git a/Documentation/btrfs-device.asciidoc b/Documentation/btrfs-device.asciidoc new file mode 100644 index 00000000..075ccc5a --- /dev/null +++ b/Documentation/btrfs-device.asciidoc @@ -0,0 +1,142 @@ +btrfs-device(8) +=============== + +NAME +---- +btrfs-device - control btrfs devices + +SYNOPSIS +-------- +*btrfs device* <subcommand> <args> + +DESCRIPTION +----------- +*btrfs device* is used to control the btrfs devices, since btrfs can be used +across several devices, *btrfs device* is used for multiple device management. + +DEVICE MANAGEMENT +----------------- +Btrfs filesystem is capable to manage multiple devices. + +Btrfs filesystem uses different profiles to manage different RAID level, and +use balance to rebuild chunks, also devices can be added/removed/replace +online. + +Profile:: +Btrfs filesystem uses data/metadata profiles to manage allocation/duplication +mechanism. + +Profiles like RAID level can be assigned to data and metadata separately. ++ +See `mkfs.btrfs`(8) for more details. + +RAID level:: +Btrfs filesystem supports most of the standard RAID level: 0/1/5/6/10. + +RAID levels can be assigned at mkfs time or online. ++ +See `mkfs.btrfs`(8) for mkfs time RAID level assign and `btrfs-balance`(8) for +online RAID level assign. ++ +NOTE: Since btrfs is under heavy development especially the RAID5/6 support, +it is *highly* recommended to read the follow btrfs wiki page to get more +updated details on RAID5/6: + +https://btrfs.wiki.kernel.org/index.php/RAID56 + +Balance:: +`btrfs-balance`(8) subcommand can be used to balance or rebuild chunks to the +desired profile. ++ +Due to the fact that balance can rebuild/recovery chunks according to its RAID +duplication if possible, so when using RAID1/5/6/10 with some devices failed +and you just added a new device to btrfs using `btrfs-device`(8), you should +run `btrfs-balance`(8) to rebuild the chunks. ++ +See `btrfs-balance`(8) for more details. + +Device add/remove/replace:: +Device can be added/removed using `btrfs-replace`(8) subcommand and replaced +using `btrfs-replace`(8). ++ +When device is removed or replaced, btrfs will do the chunk rebuild if needed. ++ +See `btrfs-replace`(8) and this man page for more details. + +SUBCOMMAND +---------- +*add* [-Kf] <dev> [<dev>...] <path>:: +Add device(s) to the filesystem identified by <path>. ++ +If applicable, a whole device discard (TRIM) operation is performed. ++ +`Options` ++ +-K|--nodiscard:::: +do not perform discard by default +-f|--force:::: +force overwrite of existing filesystem on the given disk(s) + +*delete* <dev> [<dev>...] <path>:: +Remove device(s) from a filesystem identified by <path>. + +*ready* <device>:: +Check device to see if it has all of it's devices in cache for mounting. + +*scan* [(--all-devices|-d)|<device> [<device>...]]:: +Scan devices for a btrfs filesystem. ++ +If one or more devices are passed, these are scanned for a btrfs filesystem. +If no devices are passed, btrfs uses block devices containing btrfs +filesystem as listed by blkid. +Finally, if '--all-devices' or '-d' is passed, all the devices under /dev are +scanned. + +*stats* [-z] <path>|<device>:: +Read and print the device IO stats for all mounted devices of the filesystem +identified by <path> or for a single <device>. ++ +`Options` ++ +-z:::: +Reset stats to zero after reading them. + +*usage* [options] <path> [<path>...]:: +Show detailed information about internal allocations in devices. ++ +`Options` ++ +-b|--raw:::: +raw numbers in bytes, without the 'B' suffix +-h|--human-readable:::: +print human friendly numbers, base 1024, this is the default +-H:::: +print human friendly numbers, base 1000 +--iec:::: +select the 1024 base for the following options, according to the IEC standard +--si:::: +select the 1000 base for the following options, according to the SI standard +-k|--kbytes:::: +show sizes in KiB, or kB with --si +-m|--mbytes:::: +show sizes in MiB, or MB with --si +-g|--gbytes:::: +show sizes in GiB, or GB with --si +-t|--tbytes:::: +show sizes in TiB, or TB with --si + +If conflicting options are passed, the last one takes precedence. + +EXIT STATUS +----------- +*btrfs device* returns a zero exit status if it succeeds. Non zero is +returned in case of failure. + +AVAILABILITY +------------ +*btrfs* is part of btrfs-progs. +Please refer to the btrfs wiki http://btrfs.wiki.kernel.org for +further details. + +SEE ALSO +-------- +`mkfs.btrfs`(8), +`btrfs-replace`(8), +`btrfs-balance`(8) |