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
   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 extimate 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)

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