.\"
.TH TUNE2FS 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
.SH NAME
-tune2fs \- adjust tunable filesystem parameters on ext2/ext3/ext4 filesystems
+tune2fs \- adjust tunable file system parameters on ext2/ext3/ext4 file systems
.SH SYNOPSIS
.B tune2fs
[
device
.SH DESCRIPTION
.B tune2fs
-allows the system administrator to adjust various tunable filesystem
-parameters on Linux ext2, ext3, or ext4 filesystems. The current values
+allows the system administrator to adjust various tunable file system
+parameters on Linux ext2, ext3, or ext4 file systems. The current values
of these options can be displayed by using the
.B -l
option to
.SH OPTIONS
.TP
.BI \-c " max-mount-counts"
-Adjust the number of mounts after which the filesystem will be checked by
+Adjust the number of mounts after which the file system will be checked by
.BR e2fsck (8).
If
.I max-mount-counts
-is 0 or \-1, the number of times the filesystem is mounted will be disregarded
+is the string "random", tune2fs will use a random value between 20 and 40.
+If
+.I max-mount-counts
+is 0 or \-1, the number of times the file system is mounted will be disregarded
by
.BR e2fsck (8)
and the kernel.
.sp
-Staggering the mount-counts at which filesystems are forcibly
-checked will avoid all filesystems being checked at one time
-when using journaled filesystems.
+Staggering the mount-counts at which file systems are forcibly
+checked will avoid all file systems being checked at one time
+when using journaled file systems.
.sp
Mount-count-dependent checking is disabled by default to avoid
-unanticipated long reboots while e2fsck does its work. However,
-you may wish to consider the consequences of disabling
-mount-count-dependent checking entirely. Bad disk drives, cables,
-memory, and kernel bugs could all corrupt a filesystem without
-marking the filesystem dirty or in error. If you are using
-journaling on your filesystem, your filesystem will
-.B never
-be marked dirty, so it will not normally be checked. A
-filesystem error detected by the kernel will still force
-an fsck on the next reboot, but it may already be too late
-to prevent data loss at that point.
-.sp
-See also the
-.B \-i
-option for time-dependent checking.
+unanticipated long reboots while e2fsck does its work. If you
+are concerned about file system corruptions caused by potential hardware
+problems of kernel bugs, a better solution than mount-count-dependent
+checking is to use the
+.BR e2scrub (8)
+program. This does require placing the file system on an LVM volume,
+however.
.TP
.BI \-C " mount-count"
-Set the number of times the filesystem has been mounted.
+Set the number of times the file system has been mounted.
If set to a greater value than the max-mount-counts parameter
set by the
.B \-c
option,
.BR e2fsck (8)
-will check the filesystem at the next reboot.
+will check the file system at the next reboot.
.TP
.BI \-e " error-behavior"
Change the behavior of the kernel code when errors are detected.
-In all cases, a filesystem error will cause
+In all cases, a file system error will cause
.BR e2fsck (8)
-to check the filesystem on the next boot.
+to check the file system on the next boot.
.I error-behavior
can be one of the following:
.RS 1.2i
Continue normal execution.
.TP
.B remount-ro
-Remount filesystem read-only.
+Remount file system read-only.
.TP
.B panic
Cause a kernel panic.
.RE
.TP
.BI \-E " extended-options"
-Set extended options for the filesystem. Extended options are comma
+Set extended options for the file system. Extended options are comma
separated, and may take an argument using the equals ('=') sign.
The following extended options are supported:
.RS 1.2i
.B clear_mmp
Reset the MMP block (if any) back to the clean state. Use only if
absolutely certain the device is not currently mounted or being
-fscked, or major filesystem corruption can result. Needs '-f'.
+fscked, or major file system corruption can result. Needs '-f'.
.TP
.BI mmp_update_interval= interval
Adjust the initial MMP update interval to
feature be enabled.
.TP
.BI stride= stride-size
-Configure the filesystem for a RAID array with
+Configure the file system for a RAID array with
.I stride-size
-filesystem blocks. This is the number of blocks read or written to disk
-before moving to next disk. This mostly affects placement of filesystem
+file system blocks. This is the number of blocks read or written to disk
+before moving to next disk. This mostly affects placement of file system
metadata like bitmaps at
.BR mke2fs (2)
time to avoid placing them on a single disk, which can hurt the performance.
It may also be used by block allocator.
.TP
.BI stripe_width= stripe-width
-Configure the filesystem for a RAID array with
+Configure the file system for a RAID array with
.I stripe-width
-filesystem blocks per stripe. This is typically be stride-size * N, where
+file system blocks per stripe. This is typically be stride-size * N, where
N is the number of data disks in the RAID (e.g. RAID 5 N+1, RAID 6 N+2).
This allows the block allocator to prevent read-modify-write of the
parity in a RAID stripe if possible when the data is written.
.TP
.BI hash_alg= hash-alg
-Set the default hash algorithm used for filesystems with hashed b-tree
+Set the default hash algorithm used for file systems with hashed b-tree
directories. Valid algorithms accepted are:
.IR legacy ,
.IR half_md4 ,
and
.IR tea .
.TP
+.BI encoding= encoding-name
+Enable the
+.I casefold
+feature in the super block and set
+.I encoding-name
+as the encoding to be used. If
+.I encoding-name
+is not specified, utf8 is used. The encoding cannot be altered if casefold
+was previously enabled.
+.TP
+.BI encoding_flags= encoding-flags
+Define parameters for file name character encoding operations. If a
+flag is not changed using this parameter, its default value is used.
+.I encoding-flags
+should be a comma-separated lists of flags to be enabled. The flags cannot be
+altered if casefold was previously enabled.
+
+The only flag that can be set right now is
+.I strict
+which means that invalid strings should be rejected by the file system.
+In the default configuration, the
+.I strict
+flag is disabled.
+.TP
.BI mount_opts= mount_option_string
Set a set of default mount options which will be used when the file
system is mounted. Unlike the bitmask-based default mount options which
and not at all by the ext2 and ext3 file system drivers.
.TP
.B force_fsck
-Set a flag in the filesystem superblock indicating that errors have been found.
+Set a flag in the file system superblock indicating that errors have been found.
This will force fsck to run at the next mount.
.TP
.B test_fs
-Set a flag in the filesystem superblock indicating that it may be
-mounted using experimental kernel code, such as the ext4dev filesystem.
+Set a flag in the file system superblock indicating that it may be
+mounted using experimental kernel code, such as the ext4dev file system.
.TP
.B ^test_fs
-Clear the test_fs flag, indicating the filesystem should only be mounted
-using production-level filesystem code.
+Clear the test_fs flag, indicating the file system should only be mounted
+using production-level file system code.
.RE
.TP
.B \-f
Force the tune2fs operation to complete even in the face of errors. This
option is useful when removing the
.B has_journal
-filesystem feature from a filesystem which has
+file system feature from a file system which has
an external journal (or is corrupted
such that it appears to have an external journal), but that
-external journal is not available. If the filesystem appears to require
+external journal is not available. If the file system appears to require
journal replay, the
.B \-f
flag must be specified twice to proceed.
.sp
.B WARNING:
-Removing an external journal from a filesystem which was not cleanly unmounted
+Removing an external journal from a file system which was not cleanly unmounted
without first replaying the external journal can result in
-severe data loss and filesystem corruption.
+severe data loss and file system corruption.
.TP
.BI \-g " group"
-Set the group which can use the reserved filesystem blocks.
+Set the group which can use the reserved file system blocks.
The
.I group
parameter can be a numerical gid or a group name. If a group name is given,
it is converted to a numerical gid before it is stored in the superblock.
.TP
.B \-i " \fIinterval-between-checks\fR[\fBd\fR|\fBm\fR|\fBw\fR]"
-Adjust the maximal time between two filesystem checks.
+Adjust the maximal time between two file system checks.
No suffix or
.B d
will interpret the number
.BR e2fsck (8).
This operation can also take a while and the file system can be
corrupted and data lost if it is interrupted while in the middle of
-converting the file system.
+converting the file system. Backing up the file system before changing
+inode size is recommended.
+.IP
+File systems with an inode size of 128 bytes do not support timestamps
+beyond January 19, 2038. Inodes which are 256 bytes or larger will
+support extended timestamps, project id's, and the ability to store some
+extended attributes in the inode table for improved performance.
.TP
.B \-j
-Add an ext3 journal to the filesystem. If the
+Add an ext3 journal to the file system. If the
.B \-J
option is not specified, the default journal parameters will be used to create
-an appropriately sized journal (given the size of the filesystem)
-stored within the filesystem. Note that you must be using a kernel
+an appropriately sized journal (given the size of the file system)
+stored within the file system. Note that you must be using a kernel
which has ext3 support in order to actually make use of the journal.
.IP
-If this option is used to create a journal on a mounted filesystem, an
+If this option is used to create a journal on a mounted file system, an
immutable file,
.BR .journal ,
-will be created in the top-level directory of the filesystem, as it is
-the only safe way to create the journal inode while the filesystem is
+will be created in the top-level directory of the file system, as it is
+the only safe way to create the journal inode while the file system is
mounted. While the ext3 journal is visible, it is not safe to
-delete it, or modify it while the filesystem is mounted; for this
+delete it, or modify it while the file system is mounted; for this
reason the file is marked immutable.
-While checking unmounted filesystems,
+While checking unmounted file systems,
.BR e2fsck (8)
will automatically move
.B .journal
-files to the invisible, reserved journal inode. For all filesystems
-except for the root filesystem, this should happen automatically and
-naturally during the next reboot cycle. Since the root filesystem is
+files to the invisible, reserved journal inode. For all file systems
+except for the root file system, this should happen automatically and
+naturally during the next reboot cycle. Since the root file system is
mounted read-only,
.BR e2fsck (8)
must be run from a rescue floppy in order to effect this transition.
.IP
On some distributions, such as Debian, if an initial ramdisk is used,
-the initrd scripts will automatically convert an ext2 root filesystem
+the initrd scripts will automatically convert an ext2 root file system
to ext3 if the
.B /etc/fstab
-file specifies the ext3 filesystem for the root filesystem in order to
+file specifies the ext3 file system for the root file system in order to
avoid requiring the use of a rescue floppy to add an ext3 journal to
-the root filesystem.
+the root file system.
.TP
.BR \-J " journal-options"
Override the default ext3 journal parameters. Journal options are comma
.RS 1.2i
.TP
.BI size= journal-size
-Create a journal stored in the filesystem of size
+Create a journal stored in the file system of size
.I journal-size
-megabytes. The size of the journal must be at least 1024 filesystem blocks
+megabytes. The size of the journal must be at least 1024 file system blocks
(i.e., 1MB if using 1k blocks, 4MB if using 4k blocks, etc.)
-and may be no more than 10,240,000 filesystem blocks.
-There must be enough free space in the filesystem to create a journal of
+and may be no more than 10,240,000 file system blocks.
+There must be enough free space in the file system to create a journal of
that size.
.TP
+.BI fast_commit_size= fast-commit-size
+Create an additional fast commit journal area of size
+.I fast-commit-size
+kilobytes.
+This option is only valid if
+.B fast_commit
+feature is enabled
+on the file system. If this option is not specified and if
+.B fast_commit
+feature is turned on, fast commit area size defaults to
+.I journal-size
+/ 64 megabytes. The total size of the journal with
+.B fast_commit
+feature set is
+.I journal-size
++ (
+.I fast-commit-size
+* 1024) megabytes. The total journal size may be no more than
+10,240,000 file system blocks or half the total file system size
+(whichever is smaller).
+.TP
.BI location =journal-location
Specify the location of the journal. The argument
.I journal-location
beginning of the file system.
@JDEV@.TP
@JDEV@.BI device= external-journal
-@JDEV@Attach the filesystem to the journal block device located on
+@JDEV@Attach the file system to the journal block device located on
@JDEV@.IR external-journal .
@JDEV@The external
@JDEV@journal must have been already created using the command
@JDEV@Note that
@JDEV@.I external-journal
@JDEV@must be formatted with the same block
-@JDEV@size as filesystems which will be using it.
+@JDEV@size as file systems which will be using it.
@JDEV@In addition, while there is support for attaching
-@JDEV@multiple filesystems to a single external journal,
+@JDEV@multiple file systems to a single external journal,
@JDEV@the Linux kernel and
@JDEV@.BR e2fsck (8)
@JDEV@do not currently support shared external journals yet.
@JDEV@.IP
@JDEV@Only one of the
@JDEV@.BR size " or " device
-@JDEV@options can be given for a filesystem.
+@JDEV@options can be given for a file system.
.TP
.B \-l
-List the contents of the filesystem superblock, including the current
+List the contents of the file system superblock, including the current
values of the parameters that can be set via this program.
.TP
.BI \-L " volume-label"
-Set the volume label of the filesystem.
-Ext2 filesystem labels can be at most 16 characters long; if
+Set the volume label of the file system.
+Ext2 file system labels can be at most 16 characters long; if
.I volume-label
is longer than 16 characters,
.B tune2fs
.BR /dev/hda5 .
.TP
.BI \-m " reserved-blocks-percentage"
-Set the percentage of the filesystem which may only be allocated
-by privileged processes. Reserving some number of filesystem blocks
+Set the percentage of the file system which may only be allocated
+by privileged processes. Reserving some number of file system blocks
for use by privileged processes is done
-to avoid filesystem fragmentation, and to allow system
+to avoid file system fragmentation, and to allow system
daemons, such as
.BR syslogd (8),
to continue to function correctly after non-privileged processes are
-prevented from writing to the filesystem. Normally, the default percentage
+prevented from writing to the file system. Normally, the default percentage
of reserved blocks is 5%.
.TP
.BI \-M " last-mounted-directory"
-Set the last-mounted directory for the filesystem.
+Set the last-mounted directory for the file system.
.TP
.BR \-o " [^]\fImount-option\fR[,...]"
-Set or clear the indicated default mount options in the filesystem.
+Set or clear the indicated default mount options in the file system.
Default mount options can be overridden by mount options specified
either in
.BR /etc/fstab (5)
.IP
More than one mount option can be cleared or set by separating
features with commas. Mount options prefixed with a
-caret character ('^') will be cleared in the filesystem's superblock;
+caret character ('^') will be cleared in the file system's superblock;
mount options without a prefix character or prefixed with a plus
-character ('+') will be added to the filesystem.
+character ('+') will be added to the file system.
.IP
The following mount options can be set or cleared using
.BR tune2fs :
.RS 1.2i
.TP
.B debug
-Enable debugging code for this filesystem.
+Enable debugging code for this file system.
.TP
.B bsdgroups
Emulate BSD behavior when creating new files: they will take the group-id
older kernels which only store and expect 16-bit values.
.TP
.B journal_data
-When the filesystem is mounted with journalling enabled, all data
+When the file system is mounted with journaling enabled, all data
(not just metadata) is committed into the journal prior to being written
-into the main filesystem.
+into the main file system.
.TP
.B journal_data_ordered
-When the filesystem is mounted with journalling enabled, all data is forced
+When the file system is mounted with journaling enabled, all data is forced
directly out to the main file system prior to its metadata being committed
to the journal.
.TP
.B journal_data_writeback
-When the filesystem is mounted with journalling enabled, data may be
-written into the main filesystem after its metadata has been committed
+When the file system is mounted with journaling enabled, data may be
+written into the main file system after its metadata has been committed
to the journal. This may increase throughput, however, it may allow old
data to appear in files after a crash and journal recovery.
.TP
.RE
.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 or prefixed with a plus
-character ('+') will be added to the filesystem. For a detailed
+Set or clear the indicated file system features (options) in the file system.
+More than one file system feature can be cleared or set by separating
+features with commas. File System features prefixed with a
+caret character ('^') will be cleared in the file system's superblock;
+file system features without a prefix character or prefixed with a plus
+character ('+') will be added to the file system. For a detailed
description of the file system features, please see the man page
.BR ext4 (5).
.IP
-The following filesystem features can be set or cleared using
+The following file system features can be set or cleared using
.BR tune2fs :
.RS 1.2i
.TP
.B 64bit
Enable the file system to be larger than 2^32 blocks.
.TP
+.B casefold
+Enable support for file system level casefolding.
+.B Tune2fs
+currently only supports setting this file system feature.
+.TP
.B dir_index
Use hashed b-trees to speed up lookups for large directories.
.TP
separate inode if necessary, increasing the limit on the size and number of
extended attributes per file.
.B Tune2fs
-currently only supports setting this filesystem feature.
+currently only supports setting this file system feature.
.TP
.B encrypt
Enable support for file system level encryption.
.B Tune2fs
-currently only supports setting this filesystem feature.
+currently only supports setting this file system feature.
.TP
.B extent
Enable the use of extent trees to store the location of data blocks in inodes.
.B Tune2fs
-currently only supports setting this filesystem feature.
+currently only supports setting this file system feature.
.TP
.B extra_isize
Enable the extended inode fields used by ext4.
enabled.
.TP
.B has_journal
-Use a journal to ensure filesystem consistency even across unclean shutdowns.
-Setting the filesystem feature is equivalent to using the
+Use a journal to ensure file system consistency even across unclean shutdowns.
+Setting the file system feature is equivalent to using the
.B \-j
option.
.TP
+.TP
+.B fast_commit
+Enable fast commit journaling feature to improve fsync latency.
+.TP
.B large_dir
Increase the limit on the number of files per directory.
.B Tune2fs
-currently only supports setting this filesystem feature.
+currently only supports setting this file system feature.
.TP
.B huge_file
Support files larger than 2 terabytes in size.
.TP
.B large_file
-Filesystem can contain files that are greater than 2GB.
+File System can contain files that are greater than 2GB.
.TP
.B metadata_csum
Store a checksum to protect the contents in each metadata block.
.TP
.B metadata_csum_seed
-Allow the filesystem to store the metadata checksum seed in the
-superblock, enabling the administrator to change the UUID of a filesystem
+Allow the file system to store the metadata checksum seed in the
+superblock, enabling the administrator to change the UUID of a file system
using the
.B metadata_csum
feature while it is mounted.
Reserve space so the block group descriptor table may grow in the
future.
.B Tune2fs
-only supports clearing this filesystem feature.
+only supports clearing this file system feature.
.TP
.B sparse_super
-Limit the number of backup superblocks to save space on large filesystems.
+Limit the number of backup superblocks to save space on large file systems.
+.B Tune2fs
+currently only supports setting this file system feature.
+.TP
+.B stable_inodes
+Prevent the file system from being shrunk or having its UUID changed, in order to
+allow the use of specialized encryption settings that make use of the inode
+numbers and UUID.
.B Tune2fs
-currently only supports setting this filesystem feature.
+currently only supports setting this file system feature.
.TP
.B uninit_bg
Allow the kernel to initialize bitmaps and inode tables lazily, and to
-keep a high watermark for the unused inodes in a filesystem, to reduce
+keep a high watermark for the unused inodes in a file system, to reduce
.BR e2fsck (8)
time. The first e2fsck run after enabling this feature will take the
full time, but subsequent e2fsck runs will take only a fraction of the
.B verity
Enable support for verity protected files.
.B Tune2fs
-currently only supports setting this filesystem feature.
+currently only supports setting this file system feature.
.RE
.IP
After setting or clearing
.BR filetype ,
or
.B resize_inode
-filesystem features,
+file system features,
the file system may require being checked using
.BR e2fsck (8)
-to return the filesystem to a consistent state.
+to return the file system to a consistent state.
.B Tune2fs
will print a message requesting that the system administrator run
.BR e2fsck (8)
feature,
.B e2fsck -D
can be run to convert existing directories to the hashed B-tree format.
-Enabling certain filesystem features may prevent the filesystem from being
+Enabling certain file system features may prevent the file system from being
mounted by kernels which do not support those features. In particular, the
.B uninit_bg
and
.B flex_bg
-features are only supported by the ext4 filesystem.
+features are only supported by the ext4 file system.
.TP
.BI \-r " reserved-blocks-count"
-Set the number of reserved filesystem blocks.
+Set the number of reserved file system blocks.
.TP
.BI \-Q " quota-options"
Sets 'quota' feature on the superblock and works on the quota files for the
.RE
.TP
.BI \-T " time-last-checked"
-Set the time the filesystem was last checked using
+Set the time the file system was last checked using
.BR e2fsck .
The time is interpreted using the current (local) timezone.
This can be useful in scripts which use a Logical Volume Manager to make
-a consistent snapshot of a filesystem, and then check the filesystem
+a consistent snapshot of a file system, and then check the file system
during off hours to make sure it hasn't been corrupted due to
-hardware problems, etc. If the filesystem was clean, then this option can
-be used to set the last checked time on the original filesystem. The format
+hardware problems, etc. If the file system was clean, then this option can
+be used to set the last checked time on the original file system. The format
of
.I time-last-checked
is the international date format, with an optional time specifier, i.e.
current time.
.TP
.BI \-u " user"
-Set the user who can use the reserved filesystem blocks.
+Set the user who can use the reserved file system blocks.
.I user
can be a numerical uid or a user name. If a user name is given, it
is converted to a numerical uid before it is stored in the superblock.
.TP
.BI \-U " UUID"
-Set the universally unique identifier (UUID) of the filesystem to
+Set the universally unique identifier (UUID) of the file system to
.IR UUID .
The format of the UUID is a series of hex digits separated by hyphens,
like this:
.RS 1.2i
.TP
.I clear
-clear the filesystem UUID
+clear the file system UUID
.TP
.I random
generate a new randomly-generated UUID
git://git.whamcloud.com / tools / e2fsprogs.git / blobdiff