.\"  Copyright (C) 2010 Jiro SEKIBA <jir@unicus.jp>
.\"
.TH NILFS-TUNE 8 "Apr 2014" "nilfs-utils version 2.2"
.SH NAME
nilfs-tune \- adjust tunable file system parameters on NILFS file system
.SH SYNOPSIS
.B nilfs-tune
[\fIoptions\fP] \fIdevice\fP
.SH DESCRIPTION
.B nilfs-tune
is a utility to modify tunable file system parameters on NILFS2 file
system in \fIdevice\fP.
.PP
This command is valid for inactive NILFS2 file systems.
Modifying active mounts may cause severe damage.
.SH OPTIONS
.TP
.B \-f
Force to modify even the specified file system is mounted.
.TP
.B \-i \fIinterval\fP
Set the commit interval of segment.
.TP
.B \-m \fIblock-max\fP
Set the threshold of the data amount of the segment construction.
.TP
.B \-l
List the contents of the file system superblock, including the current
values of the parameters that can be set via this program.
.TP
.B \-L \fIvolume-label\fP
Set the volume label of the file system.  NILFS2 file system labels
can be at most 80 bytes long.  If volume-label is longer than 80 bytes,
nilfs-tune will truncate it.  The volume label can be used mount(8) and
/etc/fstab(5) (and possibly others) by specifying \fBLABEL\fP=volume-label
instead of a block special device name like /dev/sda5.
.TP
.BR \-O " [^]\fIfeature\fR[,...]"
Set or clear the indicated filesystem features (options) in the filesystem.
More than one filesystem feature can be cleared or set by separating
features with commas.  Filesystem features prefixed with a
caret character ('^') will be cleared in the filesystem's superblock;
filesystem features without a prefix character
will be added to the filesystem.
.IP
The following filesystem feature can be set or cleared using
.BR nilfs-tune :
.RS
.TP
.B block_count
Enable block count per checkpoint.
After setting this option, fsck should be run on the filesystem to
make the counts right, but no fsck tool is available yet, sorry.
.RE
.TP
.B \-U \fIUUID\fP
Set the universally unique identifier (UUID) of the file system to UUID.
The format of the UUID is a series of hex digits separated by hyphens,
like this: "c1b9d5a2-f162-11cf-9ece-0020afc76f16".
.TP
.B \-h
Display help message and exit.
.SH AUTHOR
Jiro SEKIBA <jir@unicus.jp>
.SH AVAILABILITY
.B nilfs-tune
is part of the nilfs-utils package and is available from
https://nilfs.sourceforge.io.
.SH SEE ALSO
.BR nilfs (8),
.BR lscp (1),
.BR chcp (8),
.BR mkcp (8),
.BR rmcp (8).