resize/resize2fs.8.in

   1 .\" -*- nroff -*-
   2 .\" Copyright 1997 by Theodore Ts'o.  All Rights Reserved.
   3 .\"
   4 .\" .TH RESIZE2FS 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
   5 .TH RESIZE2FS 8 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
   6 .SH NAME
   7 resize2fs \- ext2/ext3/ext4 file system resizer
   8 .SH SYNOPSIS
   9 .B resize2fs
  10 [
  11 .B \-fFpPMbs
  12 ]
  13 [
  14 .B \-d
  15 .I debug-flags
  16 ]
  17 [
  18 .B \-S
  19 .I RAID-stride
  20 ]
  21 [
  22 .B \-z
  23 .I undo_file
  24 ]
  25 .I device
  26 [
  27 .I size
  28 ]
  29 .SH DESCRIPTION
  30 The
  31 .B resize2fs
  32 program will resize ext2, ext3, or ext4 file systems.  It can be used to
  33 enlarge or shrink an unmounted file system located on
  34 .IR device .
  35 If the filesystem is mounted, it can be used to expand the size of the
  36 mounted filesystem, assuming the kernel and the file system supports
  37 on-line resizing.  (Modern Linux 2.6 kernels will support on-line resize
  38 for file systems mounted using ext3 and ext4; ext3 file systems will
  39 require the use of file systems with the resize_inode feature enabled.)
  40 .PP
  41 The
  42 .I size
  43 parameter specifies the requested new size of the filesystem.
  44 If no units are specified, the units of the
  45 .I size
  46 parameter shall be the filesystem blocksize of the filesystem.
  47 Optionally, the
  48 .I size
  49 parameter may be suffixed by one of the following units
  50 designators: 'K', 'M', 'G', 'T' (either upper-case or lower-case) or 's'
  51 for power-of-two kilobytes, megabytes, gigabytes, terabytes or 512 byte
  52 sectors respectively. The
  53 .I size
  54 of the filesystem may never be larger than the size of the partition.
  55 If
  56 .I size
  57 parameter is not specified, it will default to the size of the partition.
  58 .PP
  59 The
  60 .B resize2fs
  61 program does not manipulate the size of partitions.  If you wish to enlarge
  62 a filesystem, you must make sure you can expand the size of the
  63 underlying partition first.  This can be done using
  64 .BR fdisk (8)
  65 by deleting the partition and recreating it with a larger size or using
  66 .BR lvextend (8),
  67 if you're using the logical volume manager
  68 .BR lvm (8).
  69 When
  70 recreating the partition, make sure you create it with the same starting
  71 disk cylinder as before!  Otherwise, the resize operation will
  72 certainly not work, and you may lose your entire filesystem.
  73 After running
  74 .BR fdisk (8),
  75 run resize2fs to resize the ext2 filesystem
  76 to use all of the space in the newly enlarged partition.
  77 .PP
  78 If you wish to shrink an ext2 partition, first use
  79 .B resize2fs
  80 to shrink the size of filesystem.  Then you may use
  81 .BR fdisk (8)
  82 to shrink the size of the partition.  When shrinking the size of
  83 the partition, make sure you do not make it smaller than the new size
  84 of the ext2 filesystem!
  85 .PP
  86 The
  87 .B \-b
  88 and
  89 .B \-s
  90 options enable and disable the 64bit feature, respectively.  The resize2fs
  91 program will, of course, take care of resizing the block group descriptors
  92 and moving other data blocks out of the way, as needed.  It is not possible
  93 to resize the filesystem concurrent with changing the 64bit status.
  94 .SH OPTIONS
  95 .TP
  96 .B \-b
  97 Turns on the 64bit feature, resizes the group descriptors as necessary, and
  98 moves other metadata out of the way.
  99 .TP
 100 .B \-d \fIdebug-flags
 101 Turns on various resize2fs debugging features, if they have been compiled
 102 into the binary.
 103 .I debug-flags
 104 should be computed by adding the numbers of the desired features
 105 from the following list:
 106 .br
 107         2       \-\ Debug block relocations
 108 .br
 109         4       \-\ Debug inode relocations
 110 .br
 111         8       \-\ Debug moving the inode table
 112 .br
 113         16      \-\ Print timing information
 114 .br
 115         32      \-\ Debug minimum filesystem size (\-M) calculation
 116 .TP
 117 .B \-f
 118 Forces resize2fs to proceed with the filesystem resize operation, overriding
 119 some safety checks which resize2fs normally enforces.
 120 .TP
 121 .B \-F
 122 Flush the filesystem device's buffer caches before beginning.  Only
 123 really useful for doing
 124 .B resize2fs
 125 time trials.
 126 .TP
 127 .B \-M
 128 Shrink the file system to minimize its size as much as possible,
 129 given the files stored in the file system.
 130 .TP
 131 .B \-p
 132 Prints out a percentage completion bars for each
 133 .B resize2fs
 134 operation during an offline resize, so that the user can keep track
 135 of what the program is doing.
 136 .TP
 137 .B \-P
 138 Print an estimate of the number of file system blocks in the file system
 139 if it is shrunk using
 140 .BR resize2fs 's
 141 .B \-M
 142 option and then exit.
 143 .TP
 144 .B \-s
 145 Turns off the 64bit feature and frees blocks that are no longer in use.
 146 .TP
 147 .B \-S \fIRAID-stride
 148 The
 149 .B resize2fs
 150 program will heuristically determine the RAID stride that was specified
 151 when the filesystem was created.  This option allows the user to
 152 explicitly specify a RAID stride setting to be used by resize2fs instead.
 153 .TP
 154 .BI \-z " undo_file"
 155 Before overwriting a file system block, write the old contents of the block to
 156 an undo file.  This undo file can be used with e2undo(8) to restore the old
 157 contents of the file system should something go wrong.  If the empty string is
 158 passed as the undo_file argument, the undo file will be written to a file named
 159 resize2fs-\fIdevice\fR.e2undo in the directory specified via the
 160 \fIE2FSPROGS_UNDO_DIR\fR environment variable.
 161
 162 WARNING: The undo file cannot be used to recover from a power or system crash.
 163 .SH KNOWN BUGS
 164 The minimum size of the filesystem as estimated by resize2fs may be
 165 incorrect, especially for filesystems with 1k and 2k blocksizes.
 166 .SH AUTHOR
 167 .B resize2fs
 168 was written by Theodore Ts'o <tytso@mit.edu>.
 169 .SH COPYRIGHT
 170 Resize2fs is Copyright 1998 by Theodore Ts'o and PowerQuest, Inc.  All
 171 rights reserved.
 172 As of April, 2000
 173 .B Resize2fs
 174 may be redistributed under the terms of the GPL.
 175 .SH SEE ALSO
 176 .BR fdisk (8),
 177 .BR e2fsck (8),
 178 .BR mke2fs (8),
 179 .BR lvm (8),
 180 .BR lvextend (8)