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 the units
  50 designators: 's', 'K', 'M', or 'G',
  51 for 512 byte sectors, kilobytes, megabytes, or gigabytes, respectively.
  52 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 Note: when kilobytes is used above, I mean
  60 .IR real ,
  61 power-of-2 kilobytes, (i.e., 1024 bytes), which some politically correct
  62 folks insist should be the stupid-sounding ``kibibytes''.  The same
  63 holds true for megabytes, also sometimes known as ``mebibytes'', or
  64 gigabytes, as the amazingly silly ``gibibytes''.  Makes you want to
  65 gibber, doesn't it?
  66 .PP
  67 The
  68 .B resize2fs
  69 program does not manipulate the size of partitions.  If you wish to enlarge
  70 a filesystem, you must make sure you can expand the size of the
  71 underlying partition first.  This can be done using
  72 .BR fdisk (8)
  73 by deleting the partition and recreating it with a larger size or using
  74 .BR lvextend (8),
  75 if you're using the logical volume manager
  76 .BR lvm (8).
  77 When
  78 recreating the partition, make sure you create it with the same starting
  79 disk cylinder as before!  Otherwise, the resize operation will
  80 certainly not work, and you may lose your entire filesystem.
  81 After running
  82 .BR fdisk (8),
  83 run resize2fs to resize the ext2 filesystem
  84 to use all of the space in the newly enlarged partition.
  85 .PP
  86 If you wish to shrink an ext2 partition, first use
  87 .B resize2fs
  88 to shrink the size of filesystem.  Then you may use
  89 .BR fdisk (8)
  90 to shrink the size of the partition.  When shrinking the size of
  91 the partition, make sure you do not make it smaller than the new size
  92 of the ext2 filesystem!
  93 .PP
  94 The
  95 .B \-b
  96 and
  97 .B \-s
  98 options enable and disable the 64bit feature, respectively.  The resize2fs
  99 program will, of course, take care of resizing the block group descriptors
 100 and moving other data blocks out of the way, as needed.  It is not possible
 101 to resize the filesystem concurrent with changing the 64bit status.
 102 .SH OPTIONS
 103 .TP
 104 .B \-b
 105 Turns on the 64bit feature, resizes the group descriptors as necessary, and
 106 moves other metadata out of the way.
 107 .TP
 108 .B \-d \fIdebug-flags
 109 Turns on various resize2fs debugging features, if they have been compiled
 110 into the binary.
 111 .I debug-flags
 112 should be computed by adding the numbers of the desired features
 113 from the following list:
 114 .br
 115         2       \-\ Debug block relocations
 116 .br
 117         4       \-\ Debug inode relocations
 118 .br
 119         8       \-\ Debug moving the inode table
 120 .br
 121         16      \-\ Print timing information
 122 .br
 123         32      \-\ Debug minimum filesystem size (\-M) calculation
 124 .TP
 125 .B \-f
 126 Forces resize2fs to proceed with the filesystem resize operation, overriding
 127 some safety checks which resize2fs normally enforces.
 128 .TP
 129 .B \-F
 130 Flush the filesystem device's buffer caches before beginning.  Only
 131 really useful for doing
 132 .B resize2fs
 133 time trials.
 134 .TP
 135 .B \-M
 136 Shrink the file system to minimize its size as much as possible,
 137 given the files stored in the file system.
 138 .TP
 139 .B \-p
 140 Prints out a percentage completion bars for each
 141 .B resize2fs
 142 operation during an offline resize, so that the user can keep track
 143 of what the program is doing.
 144 .TP
 145 .B \-P
 146 Print an estimate of the number of file system blocks in the file system
 147 if it is shrunk using
 148 .BR resize2fs 's
 149 .B \-M
 150 option and then exit.
 151 .TP
 152 .B \-s
 153 Turns off the 64bit feature and frees blocks that are no longer in use.
 154 .TP
 155 .B \-S \fIRAID-stride
 156 The
 157 .B resize2fs
 158 program will heuristically determine the RAID stride that was specified
 159 when the filesystem was created.  This option allows the user to
 160 explicitly specify a RAID stride setting to be used by resize2fs instead.
 161 .TP
 162 .BI \-z " undo_file"
 163 Before overwriting a file system block, write the old contents of the block to
 164 an undo file.  This undo file can be used with e2undo(8) to restore the old
 165 contents of the file system should something go wrong.  If the empty string is
 166 passed as the undo_file argument, the undo file will be written to a file named
 167 resize2fs-\fIdevice\fR.e2undo in the directory specified via the
 168 \fIE2FSPROGS_UNDO_DIR\fR environment variable.
 169
 170 WARNING: The undo file cannot be used to recover from a power or system crash.
 171 .SH KNOWN BUGS
 172 The minimum size of the filesystem as estimated by resize2fs may be
 173 incorrect, especially for filesystems with 1k and 2k blocksizes.
 174 .SH AUTHOR
 175 .B resize2fs
 176 was written by Theodore Ts'o <tytso@mit.edu>.
 177 .SH COPYRIGHT
 178 Resize2fs is Copyright 1998 by Theodore Ts'o and PowerQuest, Inc.  All
 179 rights reserved.
 180 As of April, 2000
 181 .B Resize2fs
 182 may be redistributed under the terms of the GPL.
 183 .SH SEE ALSO
 184 .BR fdisk (8),
 185 .BR e2fsck (8),
 186 .BR mke2fs (8),
 187 .BR lvm (8),
 188 .BR lvextend (8)