btrfs-device(8) =============== NAME ---- btrfs-device - control btrfs devices SYNOPSIS -------- *btrfs device* 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] [...] :: Add device(s) to the filesystem identified by . + 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* [...] :: Remove device(s) from a filesystem identified by . *scan* [(--all-devices|-d)| [...]]:: 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. *ready* :: Check device to see if it has all of it's devices in cache for mounting. *stats* [-z] |:: Read and print the device IO stats for all devices of the filesystem identified by or for a single . + `Options` + -z:::: Reset stats to zero after reading them. *usage* [options] [...]:: Show detailed information about internal allocations in devices. + `Options` + -b|--raw:::: raw numbers in bytes, without the 'B' suffix -h:::: 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)