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Diffstat (limited to 'Documentation/btrfs-scrub.8')
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diff --git a/Documentation/btrfs-scrub.8 b/Documentation/btrfs-scrub.8 new file mode 100644 index 00000000..a393a553 --- /dev/null +++ b/Documentation/btrfs-scrub.8 @@ -0,0 +1,189 @@ +'\" t +.\" Title: btrfs-scrub +.\" Author: [FIXME: author] [see http://www.docbook.org/tdg5/en/html/author] +.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/> +.\" Date: 12/05/2018 +.\" Manual: Btrfs Manual +.\" Source: Btrfs v4.19.1 +.\" Language: English +.\" +.TH "BTRFS\-SCRUB" "8" "12/05/2018" "Btrfs v4\&.19\&.1" "Btrfs Manual" +.\" ----------------------------------------------------------------- +.\" * Define some portability stuff +.\" ----------------------------------------------------------------- +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.\" http://bugs.debian.org/507673 +.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html +.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +.ie \n(.g .ds Aq \(aq +.el .ds Aq ' +.\" ----------------------------------------------------------------- +.\" * set default formatting +.\" ----------------------------------------------------------------- +.\" disable hyphenation +.nh +.\" disable justification (adjust text to left margin only) +.ad l +.\" ----------------------------------------------------------------- +.\" * MAIN CONTENT STARTS HERE * +.\" ----------------------------------------------------------------- +.SH "NAME" +btrfs-scrub \- scrub btrfs filesystem, verify block checksums +.SH "SYNOPSIS" +.sp +\fBbtrfs scrub\fR \fI<subcommand>\fR \fI<args>\fR +.SH "DESCRIPTION" +.sp +\fBbtrfs scrub\fR is used to scrub a btrfs filesystem, which will read all data and metadata blocks from all devices and verify checksums\&. Automatically repair corrupted blocks if there\(cqs a correct copy available\&. +.if n \{\ +.sp +.\} +.RS 4 +.it 1 an-trap +.nr an-no-space-flag 1 +.nr an-break-flag 1 +.br +.ps +1 +\fBNote\fR +.ps -1 +.br +.sp +Scrub is not a filesystem checker (fsck) and does not verify nor repair structural damage in the filesystem\&. +.sp .5v +.RE +.sp +The user is supposed to run it manually or via a periodic system service\&. The recommended period is a month but could be less\&. The estimated device bandwidth utilization is about 80% on an idle filesystem\&. The IO priority class is by default \fIidle\fR so background scrub should not significantly interfere with normal filesystem operation\&. +.sp +The scrubbing status is recorded in \fI/var/lib/btrfs/\fR in textual files named \fIscrub\&.status\&.UUID\fR for a filesystem identified by the given UUID\&. (Progress state is communicated through a named pipe in file \fIscrub\&.progress\&.UUID\fR in the same directory\&.) The status file is updated every 5 seconds\&. A resumed scrub will continue from the last saved position\&. +.SH "SUBCOMMAND" +.PP +\fBcancel\fR \fI<path>\fR|\fI<device>\fR +.RS 4 +If a scrub is running on the filesystem identified by +\fIpath\fR +cancel it\&. +.sp +If a +\fIdevice\fR +is specified, the corresponding filesystem is found and +\fBbtrfs scrub cancel\fR +behaves as if it was called on that filesystem\&. +.RE +.PP +\fBresume\fR [\-BdqrR] [\-c \fI<ioprio_class>\fR \-n \fI<ioprio_classdata>\fR] \fI<path>\fR|\fI<device>\fR +.RS 4 +Resume a cancelled or interrupted scrub on the filesystem identified by +\fIpath\fR +or on a given +\fIdevice\fR\&. +.sp +Does not start a new scrub if the last scrub finished successfully\&. +.sp +\fBOptions\fR +.sp +see +\fBscrub start\fR\&. +.RE +.PP +\fBstart\fR [\-BdqrRf] [\-c \fI<ioprio_class>\fR \-n \fI<ioprio_classdata>\fR] \fI<path>\fR|\fI<device>\fR +.RS 4 +Start a scrub on all devices of the filesystem identified by +\fIpath\fR +or on a single +\fIdevice\fR\&. If a scrub is already running, the new one fails\&. +.sp +Without options, scrub is started as a background process\&. +.sp +The default IO priority of scrub is the idle class\&. The priority can be configured similar to the +\fBionice\fR(1) syntax using +\fI\-c\fR +and +\fI\-n\fR +options\&. +.sp +\fBOptions\fR +.PP +\-B +.RS 4 +do not background and print scrub statistics when finished +.RE +.PP +\-d +.RS 4 +print separate statistics for each device of the filesystem (\fI\-B\fR +only) at the end +.RE +.PP +\-q +.RS 4 +be quiet, omit error messages and statistics +.RE +.PP +\-r +.RS 4 +run in read\-only mode, do not attempt to correct anything, can be run on a read\-only filesystem +.RE +.PP +\-R +.RS 4 +raw print mode, print full data instead of summary +.RE +.PP +\-c \fI<ioprio_class>\fR +.RS 4 +set IO priority class (see +\fBionice\fR(1) manpage) +.RE +.PP +\-n \fI<ioprio_classdata>\fR +.RS 4 +set IO priority classdata (see +\fBionice\fR(1) manpage) +.RE +.PP +\-f +.RS 4 +force starting new scrub even if a scrub is already running, this can useful when scrub status file is damaged and reports a running scrub although it is not, but should not normally be necessary +.RE +.RE +.PP +\fBstatus\fR [\-d] \fI<path>\fR|\fI<device>\fR +.RS 4 +Show status of a running scrub for the filesystem identified by +\fIpath\fR +or for the specified +\fIdevice\fR\&. +.sp +If no scrub is running, show statistics of the last finished or cancelled scrub for that filesystem or device\&. +.sp +\fBOptions\fR +.PP +\-d +.RS 4 +print separate statistics for each device of the filesystem +.RE +.RE +.SH "EXIT STATUS" +.sp +\fBbtrfs scrub\fR returns a zero exit status if it succeeds\&. Non zero is returned in case of failure: +.PP +1 +.RS 4 +scrub couldn\(cqt be performed +.RE +.PP +2 +.RS 4 +there is nothing to resume +.RE +.PP +3 +.RS 4 +scrub found uncorrectable errors +.RE +.SH "AVAILABILITY" +.sp +\fBbtrfs\fR is part of btrfs\-progs\&. Please refer to the btrfs wiki \m[blue]\fBhttp://btrfs\&.wiki\&.kernel\&.org\fR\m[] for further details\&. +.SH "SEE ALSO" +.sp +\fBmkfs\&.btrfs\fR(8), \fBionice\fR(1) |