TUNE2FS

tune2fs ? adjust tunable filesystem parameters on second extended filesystems

tune2fs [ ?l ] [ ?c max-mount-counts ] [ ?e errors-behavior ] [ ?i interval-between-checks ] [ ?m reserved-blocks-percentage ] [ ?r reserved-blocks-count ] [ ?s sparse-super-flag ] [ ?u user ] [ ?g group ] [ ?C mount-count ] [ ?L volume-name ] [ ?M last-mounted-directory ] [ ?O [^]feature[,...] ] [ ?U UUID ] device

tune2fs adjusts tunable filesystem parameters on a Linux second extended filesystem.

?c max-mount-counts

adjust the maximal mounts count between two filesystem checks.

?e error-behavior

change the behavior of the kernel code when errors are detected. error-behavior can be one of the following:

continue

Continue normal execution.

remount-ro

Remount filesystem read-only.

panic

Cause a kernel panic.

?g group

set the user group which can benefit from the reserved blocks.
group can be a numerical gid or a group name.

?i interval-between-checks[d|m|w]

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 timedependent checking.

?l

list the contents of the filesystem superblock.

?m reserved-blocks-percentage

adjust the reserved blocks percentage on the given device.

?r reserved-blocks-count

adjust the reserved blocks count on the given device.

?s sparse_super_flag

set or reset the sparse_superblock flag. The sparse_superblock feature saves space on really big filesystems. Warning: The Linux 2.0 kernel does not properly support this feature. Neither do all Linux 2.1 kernels; please don’t use this unless you know what you’re doing!

?u user

set the user who can benefit from the reserved blocks. user can be a numerical uid or a user name.

?C mount-count

set the number of times the filesystem has been mounted.

?L volume-label

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 message.

?M last-mounted-directory

set the last-mounted directory for the filesystem.

?O [^]feature[,...]

set or clear the indicated filesystem features (options) in the filesystem. Feature can be one of the following supported filesystem options: sparse, which cause the filesystem to use sparse superblocks, and filetype, which will cause the filesystem to store file type information in directory entries. After setting or clearing either filesystem feature, e2fsck must be run on the filesystem.

?U UUID

set the UUID of the filesystem. A sample UUID looks like this: "c1b9d5a2-f162-11cf-9ece-0020afc76f16". The uuid may also be null, which will set the filesystem UUID to the null UUID. The uuid may also be random, which will generate a new random UUID for the filesystem.

We haven’t found any bugs yet. Perhaps there are bugs but it’s unlikely.

Never use tune2fs to change parameters of a read/write mounted filesystem! Use this utility at your own risk. You’re modifying a filesystem!

tune2fs was written by Remy Card <card@masi.ibp.fr>, the developer and maintainer of the ext2 fs. tune2fs uses the ext2fs library written by Theodore Ts’o <tytso@mit.edu>. This manual page was written by Christian Kuhtz <chk@data-hh.Hanse.DE>. Timedependent checking was added by Uwe Ohse <uwe@tirka.gun.de>.

tune2fs is part of the e2fsprogs package and is available for anonymous ftp from tsx-11.mit.edu in /pub/linux/packages/ext2fs.

dumpe2fs(8), e2fsck(8), mke2fs(8)