SYNOPSIS

btrfs scrub <subcommand> <args>

DESCRIPTION

btrfs scrub is used to scrub a btrfs filesystem, which will read all data from all disks and verify checksums.

SUBCOMMAND

cancel <path>|<device>

If a scrub is running on the filesystem identified by <path>, cancel it.

Progress is saved in the scrub progress file and scrubbing can be resumed later using the scrub resume command. If a <device> is given, the corresponding filesystem is found and scrub cancel behaves as if it was called on that filesystem.

resume [-BdqrR] [-c <ioprio_class> -n <ioprio_classdata>] <path>|<device>

Resume a cancelled or interrupted scrub cycle on the filesystem identified by <path> or on a given <device>.

Does not start a new scrub if the last scrub finished successfully.

Options

see scrub start.

start [-BdqrRf] [-c <ioprio_class> -n <ioprio_classdata>] <path>|<device>

Start a scrub on all devices of the filesystem identified by <path> or on a single <device>. If a scrub is already running, the new one fails.

Without options, scrub is started as a background process. Progress can be obtained with the scrub status command. Scrubbing involves reading all data from all disks and verifying checksums. Errors are corrected along the way if possible.

The default IO priority of scrub is the idle class. The priority can be configured similar to the ionice(1) syntax using -c and -n options.

Options

-B

Do not background and print scrub statistics when finished.

-d

Print separate statistics for each device of the filesystem (-B only).

-q

Quiet. Omit error messages and statistics.

-r

Read only mode. Do not attempt to correct anything.

-R

Raw print mode. Print full data instead of summary.

-c <ioprio_class>

Set IO priority class (see ionice(1) manpage).

-n <ioprio_classdata>

Set IO priority classdata (see ionice(1) manpage).

-f

Force starting new scrub even if a scrub is already running. This is useful when scrub status record file is damaged.

status [-d] <path>|<device>

Show status of a running scrub for the filesystem identified by <path> or for the specified <device>.

If no scrub is running, show statistics of the last finished or cancelled scrub for that filesystem or device.

Options

-d

Print separate statistics for each device of the filesystem.

AVAILABILITY

btrfs is part of btrfs-progs. Please refer to the btrfs wiki m[blue]http://btrfs.wiki.kernel.orgm[] for further details.