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Adjust the number of mounts after which the filesystem will be checked by
max-mount-counts is 0 or -1, the number of times the filesystem is mounted will be disregarded
and the kernel.
Staggering the mount-counts at which filesystems are forcibly checked will avoid all filesystems being checked at one time when using journaled filesystems.
You should strongly 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 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.
See also the -i option for time-dependent checking.
|Set the number of times the filesystem has been mounted. If set to a greater value than the max-mount-counts parameter set by the -c option, e2fsck(8) will check the filesystem at the next reboot.|
|Change the behavior of the kernel code when errors are detected. In all cases, a filesystem error will cause e2fsck(8) to check the filesystem on the next boot. error-behavior can be one of the following:|
Force the tune2fs operation to complete even in the face of errors. This
option is useful when removing the
has_journal filesystem feature from a filesystem which has
an external journal (or is corrupted
such that it appears to have an external journal), but that
external journal is not available.
WARNING: Removing an external journal from a filesystem which was not cleanly unmounted without first replaying the external journal can result in severe data loss and filesystem corruption.
|-g group||Set the group which can use reserved filesystem blocks. The 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.|
Adjust the maximal time between two filesystem checks.
No postfix or
d result in days,
m in months, and
w in weeks. A value of zero will disable the time-dependent checking.
It is strongly recommended that either -c (mount-count-dependent) or -i (time-dependent) checking be enabled to force periodic full e2fsck(8) checking of the filesystem. Failure to do so may lead to filesystem corruption due to bad disks, cables, memory, or kernel bugs to go unnoticed until they cause data loss or corruption.
|-j||Add an ext3 journal to the filesystem. If the -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 which has ext3 support in order to actually make use of the journal.|
|If this option is used to create a journal on a mounted filesystem, an immutable file, .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 mounted. While the ext3 journal is visible, it is not safe to delete it, or modify it while the filesystem is mounted; for this reason the file is marked immutable. While checking unmounted filesystems, e2fsck(8) will automatically move .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 mounted read-only, e2fsck(8) must be run from a rescue floppy in order to effect this transition.|
|On some distributions, such as Debian, if an initial ramdisk is used, the initrd scripts will automatically convert an ext2 root filesystem to ext3 if the /etc/fstab file specifies the ext3 filesystem for the root filesystem in order to avoid requiring the use of a rescue floppy to add an ext3 journal to the root filesystem.|
|Override the default ext3 journal parameters. Journal options are comma separated, and may take an argument using the equals (=) sign. The following journal options are supported:|
|Only one of the size or device options can be given for a filesystem.|
|-l||List the contents of the filesystem superblock.|
|Set the volume label of the filesystem. Ext2 filesystem labels can be at most 16 characters long; if volume-label is longer than 16 characters, tune2fs will truncate it and print a warning. The volume label can be used by mount(8), fsck(8), and /etc/fstab(5) (and possibly others) by specifying LABEL=volume_label instead of a block special device name like /dev/hda5.|
|Set the percentage of reserved filesystem blocks.|
|Set the last-mounted directory for the filesystem.|
|Set or clear the indicated default mount options in the filesystem. Default mount options can be overridden by mount options specified either in /etc/fstab(5) or on the command line arguments to mount(8). Older kernels may not support this feature; in particular, kernels which predate 2.4.20 will almost certainly ignore the default mount options field in the superblock.|
|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 filesystems superblock; mount options without a prefix character or prefixed with a plus character (+) will be added to the filesystem.|
|The following mount options can be set or cleared using tune2fs:|
|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 filesystems superblock; filesystem features without a prefix character or prefixed with a plus character (+) will be added to the filesystem.|
|The following filesystem features can be set or cleared using tune2fs:|
|After setting or clearing sparse_super and filetype filesystem features, e2fsck(8) must be run on the filesystem to return the filesystem to a consistent state. Tune2fs will print a message requesting that the system administrator run e2fsck(8) if necessary. After setting the dir_index feature, e2fsck -D can be run to convert existing directories to the hashed B-tree format.|
|Warning: Linux kernels before 2.0.39 and many 2.1 series kernels do not support the filesystems that use any of these features. Enabling certain filesystem features may prevent the filesystem from being mounted by kernels which do not support those features.|
|Set the number of reserved filesystem blocks.|
|-s [0|1]||Turn the sparse super feature off or on. Turning this feature on saves space on really big filesystems. This is the same as using the -O sparse_super option.|
|Warning: Linux kernels before 2.0.39 do not support this feature. Neither do all Linux 2.1 kernels; please dont use this unless you know what youre doing! You need to run e2fsck(8) on the filesystem after changing this feature in order to have a valid filesystem.|
|Set the time the filesystem was last checked using e2fsck. 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 during off hours to make sure it hasnt 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 of time-last-checked is the international date format, with an optional time specifier, i.e. YYYYMMDD[[HHMM]SS]. The keyword now is also accepted, in which case the last checked time will be set to the current time.|
|-u user||Set the user who can use the reserved filesystem blocks. 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.|
|-U UUID||Set the universally unique identifier (UUID) of the filesystem to UUID. The format of the UUID is a series of hex digits separated by hyphens, like this: "c1b9d5a2-f162-11cf-9ece-0020afc76f16". The UUID parameter may also be one of the following:|
|The UUID may be used by mount(8), fsck(8), and /etc/fstab(5) (and possibly others) by specifying UUID=uuid instead of a block special device name like /dev/hda1.|
|See uuidgen(8) for more information. If the system does not have a good random number generator such as /dev/random or /dev/urandom, tune2fs will automatically use a time-based UUID instead of a randomly-generated UUID.|
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