RESIZE2FS(8) System Manager's Manual RESIZE2FS(8)
resize2fs - ext2/ext3/ext4 file system resizer
resize2fs [ -fFpPMbs ] [ -d debug-flags ] [ -S RAID-stride ] [ -z
undo_file ] device [ size ]
The resize2fs program will resize ext2, ext3, or ext4 file systems. It
can be used to enlarge or shrink an unmounted file system located on
device. If the filesystem is mounted, it can be used to expand the
size of the mounted filesystem, assuming the kernel and the file system
supports on-line resizing. (Modern Linux 2.6 kernels will support on-
line resize for file systems mounted using ext3 and ext4; ext3 file
systems will require the use of file systems with the resize_inode fea-
The size parameter specifies the requested new size of the filesystem.
If no units are specified, the units of the size parameter shall be the
filesystem blocksize of the filesystem. Optionally, the size parameter
may be suffixed by one of the following the units designators: 's',
'K', 'M', or 'G', for 512 byte sectors, kilobytes, megabytes, or giga-
bytes, respectively. The size of the filesystem may never be larger
than the size of the partition. If size parameter is not specified, it
will default to the size of the partition.
Note: when kilobytes is used above, I mean real, power-of-2 kilobytes,
(i.e., 1024 bytes), which some politically correct folks insist should
be the stupid-sounding ``kibibytes''. The same holds true for
megabytes, also sometimes known as ``mebibytes'', or gigabytes, as the
amazingly silly ``gibibytes''. Makes you want to gibber, doesn't it?
The resize2fs program does not manipulate the size of partitions. If
you wish to enlarge a filesystem, you must make sure you can expand the
size of the underlying partition first. This can be done using
fdisk(8) by deleting the partition and recreating it with a larger size
or using lvextend(8), if you're using the logical volume manager
lvm(8). When recreating the partition, make sure you create it with
the same starting disk cylinder as before! Otherwise, the resize oper-
ation will certainly not work, and you may lose your entire filesystem.
After running fdisk(8), run resize2fs to resize the ext2 filesystem to
use all of the space in the newly enlarged partition.
If you wish to shrink an ext2 partition, first use resize2fs to shrink
the size of filesystem. Then you may use fdisk(8) to shrink the size
of the partition. When shrinking the size of the partition, make sure
you do not make it smaller than the new size of the ext2 filesystem!
The -b and -s options enable and disable the 64bit feature, respec-
tively. The resize2fs program will, of course, take care of resizing
the block group descriptors and moving other data blocks out of the
way, as needed. It is not possible to resize the filesystem concurrent
with changing the 64bit status.
-b Turns on the 64bit feature, resizes the group descriptors as
necessary, and moves other metadata out of the way.
Turns on various resize2fs debugging features, if they have been
compiled into the binary. debug-flags should be computed by
adding the numbers of the desired features from the following
2 - Debug block relocations
4 - Debug inode relocations
8 - Debug moving the inode table
16 - Print timing information
32 - Debug minimum filesystem size (-M) calculation
-f Forces resize2fs to proceed with the filesystem resize opera-
tion, overriding some safety checks which resize2fs normally
-F Flush the filesystem device's buffer caches before beginning.
Only really useful for doing resize2fs time trials.
-M Shrink the file system to minimize its size as much as possible,
given the files stored in the file system.
-p Prints out a percentage completion bars for each resize2fs oper-
ation during an offline resize, so that the user can keep track
of what the program is doing.
-P Print an estimate of the number of file system blocks in the
file system if it is shrunk using resize2fs's -M option and then
-s Turns off the 64bit feature and frees blocks that are no longer
The resize2fs program will heuristically determine the RAID
stride that was specified when the filesystem was created. This
option allows the user to explicitly specify a RAID stride set-
ting to be used by resize2fs instead.
Before overwriting a file system block, write the old contents
of the block to an undo file. This undo file can be used with
e2undo(8) to restore the old contents of the file system should
something go wrong. If the empty string is passed as the
undo_file argument, the undo file will be written to a file
named resize2fs-device.e2undo in the directory specified via the
E2FSPROGS_UNDO_DIR environment variable.
WARNING: The undo file cannot be used to recover from a power or
The minimum size of the filesystem as estimated by resize2fs may be
incorrect, especially for filesystems with 1k and 2k blocksizes.
resize2fs was written by Theodore Ts'o <email@example.com>.
Resize2fs is Copyright 1998 by Theodore Ts'o and PowerQuest, Inc. All
rights reserved. As of April, 2000 Resize2fs may be redistributed
under the terms of the GPL.
fdisk(8), e2fsck(8), mke2fs(8), lvm(8), lvextend(8)
E2fsprogs version 1.44.1 March 2018 RESIZE2FS(8)
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