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 file system is
       mounted, it can be used to expand the size of the mounted file system, 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 file system.  If no units are
       specified, the units of the size parameter shall be the file system blocksize of the  file
       system.   Optionally,  the  size  parameter  may be suffixed by one of the following units
       designators: 'K', 'M', 'G', 'T' (either upper-case or lower-case) or 's' for  power-of-two
       kilobytes,  megabytes,  gigabytes, terabytes or 512 byte sectors respectively. The size of
       the file system 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.

       The  resize2fs program does not manipulate the size of partitions.  If you wish to enlarge
       a file system, 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  file system.  After running fdisk(8), run resize2fs to resize the ext2 file system
       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  file
       system.   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 file system!

       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 file system
       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 file system size (-M) calculation

       -f     Forces  resize2fs to proceed with the file system resize operation, overriding some
              safety checks which resize2fs normally enforces.

       -F     Flush the file system 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     Print out percentage completion bars for each resize2fs  phase  during  an  offline
              (non-trivial) resize operation, so that the user can keep track of what the program
              is doing.  (For very fast resize operations, no progress bars may be displayed.)

       -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 file system  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 file system as estimated by resize2fs may be incorrect, especially
       for file systems 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)