Btrfs で RAID10

btrfs を試す 2 - Multiple Devices - ~fumi/ChangeLog に書かれているとおり。

近ごろは btrfs にコマンドが統合されつつある?

/sbin/btrfs --help
Usage:
	btrfs subvolume snapshot <source> [<dest>/]<name>
		Create a writable snapshot of the subvolume <source> with
		the name <name> in the <dest> directory.
	btrfs subvolume delete <subvolume>
		Delete the subvolume <subvolume>.
	btrfs subvolume create [<dest>/]<name>
		Create a subvolume in <dest> (or the current directory if
		not passed).
	btrfs subvolume list <path>
		List the snapshot/subvolume of a filesystem.
	btrfs subvolume find-new <path> <last_gen>
		List the recently modified files in a filesystem.
	btrfs filesystem defragment [-vcf] [-s start] [-l len] [-t size] <file>|<dir> [<file>|<dir>...]
		Defragment a file or a directory.
	btrfs subvolume set-default <id> <path>
		Set the subvolume of the filesystem <path> which will be mounted
		as default.
	btrfs filesystem sync <path>
		Force a sync on the filesystem <path>.
	btrfs filesystem resize [+/-]<newsize>[gkm]|max <filesystem>
		Resize the file system. If 'max' is passed, the filesystem
		will occupe all available space on the device.
	btrfs filesystem show [<uuid>|<label>]
		Show the info of a btrfs filesystem. If no <uuid> or <label>
		is passed, info of all the btrfs filesystem are shown.
	btrfs filesystem df <path>
		Show space usage information for a mount point
		.
	btrfs filesystem balance <path>
		Balance the chunks across the device.
	btrfs device scan [<device> [<device>..]
		Scan all device for or the passed device for a btrfs
		filesystem.
	btrfs device add <dev> [<dev>..] <path>
		Add a device to a filesystem.
	btrfs device delete <dev> [<dev>..] <path>
		Remove a device from a filesystem.

	btrfs help|--help|-h
		Show the help.

Btrfs Btrfs v0.19

RAID10 になっているかは次のように確認できる。

sudo btrfs filesystem df /mnt/btrfs
Data, RAID10: total=128.00MB, used=0.00
Data: total=8.00MB, used=0.00
System, RAID10: total=16.00MB, used=4.00KB
System: total=4.00MB, used=0.00
Metadata, RAID10: total=64.00MB, used=8.00KB
Metadata: total=8.00MB, used=16.00KB