Provided by: e2fsprogs_1.44.1-1ubuntu1.4_amd64 
NAME
resize2fs - ext2/ext3/ext4 file system resizer
SYNOPSIS
resize2fs [ -fFpPMbs ] [ -d debug-flags ] [ -S RAID-stride ] [ -z undo_file ] device [
size ]
DESCRIPTION
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 feature enabled.)
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
gigabytes, 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 operation 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, respectively. 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.
OPTIONS
-b Turns on the 64bit feature, resizes the group descriptors as necessary, and moves
other metadata out of the way.
-d debug-flags
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 list:
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 operation, overriding some
safety checks which resize2fs normally enforces.
-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 operation 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 exit.
-s Turns off the 64bit feature and frees blocks that are no longer in use.
-S RAID-stride
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 setting to be used by resize2fs instead.
-z undo_file
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 system crash.
KNOWN BUGS
The minimum size of the filesystem as estimated by resize2fs may be incorrect, especially
for filesystems with 1k and 2k blocksizes.
AUTHOR
resize2fs was written by Theodore Ts'o <tytso@mit.edu>.
COPYRIGHT
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.
SEE ALSO
fdisk(8), e2fsck(8), mke2fs(8), lvm(8), lvextend(8)