Dumpe2fs Command

Displaying ext2, ext3 and ext4 filesystem information

Dumpe2fs Command

The "dumpe2fs" command is used to display information about ext2, ext3 and ext4 filesystems. dumpe2fs displays superblock and block group information for filesystems present on a device.

Syntax: dumpe2fs [ -bfhixV ] [ -o superblock=superblock ] [ -o blocksize=blocksize ] device


 -b     print the blocks which are reserved as bad in the filesystem.

       -o superblock=superblock
              use  the  block  superblock  when examining the filesystem.  This option is not usually
              needed except by a filesystem wizard who is examining the remains of a very badly  cor-
              rupted filesystem.

       -o blocksize=blocksize
              use  blocks  of blocksize bytes when examining the filesystem.  This option is not usu-
              ally needed except by a filesystem wizard who is examining the remains of a very  badly
              corrupted filesystem.

       -f     force  dumpe2fs to display a filesystem even though it may have some filesystem feature
              flags which dumpe2fs may not understand (and which can cause some of dumpe2fs's display
              to be suspect).

       -h     only  display  the  superblock  information  and  not any of the block group descriptor
              detail information.

       -i     display the filesystem data from an image file created by e2image, using device as  the
              pathname to the image file.

       -x     print the detailed group information block numbers in hexadecimal format

       -V     print the version number of dumpe2fs and exit.

dumpe2fs - Example Display Superblock information

john@john-desktop:~$ sudo dumpe2fs -h /dev/sda1
dumpe2fs 1.42 (29-Nov-2011)
Filesystem volume name:   <none>
Last mounted on:          /
Filesystem UUID:          4daba06c-1d4d-4bbc-8f66-0a48cb20d0b4
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize
Filesystem flags:         signed_directory_hash 
Default mount options:    (none)
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              9609216
Block count:              38419456
Reserved block count:     1920972
Free blocks:              11195030
Free inodes:              8480522
First block:              0
Block size:               4096
Fragment size:            4096
Reserved GDT blocks:      1014
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         8192
Inode blocks per group:   512
Flex block group size:    16
Filesystem created:       Sat Oct 22 19:36:56 2011
Last mount time:          Tue Jul 23 19:57:51 2013
Last write time:          Wed Jul 17 12:06:55 2013
Mount count:              6
Maximum mount count:      35
Last checked:             Wed Jul 17 12:06:55 2013
Check interval:           15552000 (6 months)
Next check after:         Mon Jan 13 11:06:55 2014
Lifetime writes:          605 GB
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:	          256
Required extra isize:     28
Desired extra isize:      28
Journal inode:            8
First orphan inode:       6553671
Default directory hash:   half_md4
Directory Hash Seed:      0206aa9d-9545-4e90-886e-d76a5511ebc7
Journal backup:           inode blocks
Journal features:         journal_incompat_revoke
Journal size:             128M
Journal length:           32768
Journal sequence:         0x00242dd8
Journal start:            23267