| btrfs-qgroup(8) |
| =============== |
| |
| NAME |
| ---- |
| btrfs-qgroup - control the quota group of a btrfs filesystem |
| |
| SYNOPSIS |
| -------- |
| *btrfs qgroup* <subcommand> <args> |
| |
| DESCRIPTION |
| ----------- |
| *btrfs qgroup* is used to control quota group(qgroup) of a btrfs filesystem. |
| |
| NOTE: To use qgroup, it needs to enable quota first using *btrfs quota* |
| command. |
| |
| WARNING: Qgroup is not stable yet and will impact performance in current mainline |
| kernel(v3.14 so far). |
| |
| QGROUP |
| ------ |
| Quota group or qgroup in btrfs has its hierarchy like subvolume. |
| One subvolume/snapshot can reach its quota limits if it consumes all the quota |
| assigned to it or any of the parent qgroup(s). |
| |
| Also for snapshot, it consumes no quota initially since all its data |
| shares with its parent, so only modification in snapshot consumes quota. |
| |
| Every subvolume/snapshot will have its own qgroup with id '0/<subvolume id>' |
| upon creating, but can be later destroyed by *btrfs qgroup destroy* command. |
| |
| NOTE: If the qgroup of a subvolume is destroyed, quota about the subvolume |
| will not be functional until qgroup '0/<subvolume id>' is created again. |
| |
| SUBCOMMAND |
| ---------- |
| *assign* <src> <dst> <path>:: |
| Assign qgroup <src> as the child qgroup of <dst> in the btrfs filesystem |
| identified by <path>. |
| |
| *create* <qgroupid> <path>:: |
| Create a subvolume quota group. |
| + |
| For the '0/<subvolume id>' qgroup, a qgroup can be created even before the |
| subvolume created. |
| |
| *destroy* <qgroupid> <path>:: |
| Destroy a qgroup. |
| + |
| If a qgroup is no isolated,which means it is a parent or child qgroup, it |
| can't be destroyed. |
| |
| *limit* [options] <size>|none [<qgroupid>] <path>:: |
| Limit the size of a qgroup to <size> or no limit in the btrfs filesystem |
| identified by <path>. |
| + |
| If <qgroupid> is not given, qgroup of the subvolume identified by <path> |
| is used if possible. |
| + |
| `Options` |
| + |
| -c:::: |
| limit amount of data after compression. This is the default, it is currently not |
| possible to turn off this option. |
| + |
| -e:::: |
| limit space exclusively assigned to this qgroup. |
| |
| *remove* <src> <dst> <path>:: |
| Remove the relationship between child qgroup <src> and parent qgroup <dst> in |
| the btrfs filesystem identified by <path>. |
| |
| *show* [options] <path>:: |
| Show all qgroups in the btrfs filesystem identified by <path>. |
| + |
| `Options` |
| + |
| -p:::: |
| print parent qgroup id. |
| -c:::: |
| print child qgroup id. |
| -r:::: |
| print limit of referenced size of qgroup. |
| -e:::: |
| print limit of exclusive size of qgroup. |
| -F:::: |
| list all qgroups which impact the given path(include ancestral qgroups) |
| -f:::: |
| list all qgroups which impact the given path(exclude ancestral qgroups) |
| --raw:::: |
| raw numbers in bytes, without the 'B' suffix. |
| --human-readable:::: |
| print human friendly numbers, base 1024, this is the default |
| --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. |
| --kbytes:::: |
| show sizes in KiB, or kB with --si. |
| --mbytes:::: |
| show sizes in MiB, or MB with --si. |
| --gbytes:::: |
| show sizes in GiB, or GB with --si. |
| --tbytes:::: |
| show sizes in TiB, or TB with --si. |
| --sort=[\+/-]<attr>[,[+/-]<attr>]...:::: |
| list qgroups in order of <attr>. |
| + |
| <attr> can be one or more of qgroupid,rfer,excl,max_rfer,max_excl. |
| + |
| Prefix \'+' means ascending order and \'-' means descending order of <attr>. |
| If no prefix is given, use ascending order by default. |
| + |
| If multiple <attr>s is given, use comma to separate. |
| |
| EXIT STATUS |
| ----------- |
| *btrfs qgroup* 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-subvolume`(8), |
| `btrfs-quota`(8), |