man > resize2fs(8)

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 en‐
       large 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 desig‐
       nators: 'K', 'M', 'G', 'T' (either upper-case or lower-case) or 's'  for  power-of-two  kilo‐
       bytes, 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 speci‐
       fied, 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 recreat‐
       ing 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 sys‐
       tem.  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 pro‐
       gram 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 bi‐
              nary.   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 do‐
              ing.  (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 AT 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 1.47.0                    February 2023                               RESIZE2FS(8)