resize2fs

RESIZE2FS(8)                System Manager's Manual               RESIZE2FS(8)

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 fea-
       ture 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 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.

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  opera-
              tion,  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 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
              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 set-
              ting 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)

E2fsprogs version 1.44.1          March 2018                      RESIZE2FS(8)
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