Archive for the tag 'Superblock'

SBDavid
Apr 20th, 2010

How to find primary and backup Superblock

How to find primary and backup Superblock

dumpe2fs prints the super block and blocks group information for the filesystem present on device.

#dumpe2fs /dev/hda4 | grep -i superblock
dumpe2fs 1.39 (29-May-2006)
Primary superblock at 0, Group descriptors at 1-1
Backup superblock at 32768, Group descriptors at 32769-32769
Backup superblock at 98304, Group descriptors at 98305-98305
Backup superblock at 163840, Group descriptors at 163841-163841
Backup superblock at 229376, Group descriptors at 229377-229377
Backup superblock at 294912, Group descriptors at 294913-294913
Backup superblock at 819200, Group descriptors at 819201-819201
Backup superblock at 884736, Group descriptors at 884737-884737
Backup superblock at 1605632, Group descriptors at 1605633-1605633

Now you can use the command below to repair the file system.

e2fsck - check a Linux ext2/ext3 file system

SBDavid
Jan 5th, 2010

Superblock

Superblock

The superblock is a structure that represents a file system. It includes the necessary information to manage the file system during operation. It includes the file system name (such as ext2), the size of the file system and its state, a reference to the block device, and metadata information (such as free lists and so on). The superblock is typically stored on the storage medium but can be created in real time if one doesn’t exist.

Finding out the backup superblock.

root@dell:~# dumpe2fs /dev/sda2 |grep -i superblock
dumpe2fs 1.41.2 (02-Oct-2008)
Primary superblock at 0, Group descriptors at 1-3
Backup superblock at 32768, Group descriptors at 32769-32771
Backup superblock at 98304, Group descriptors at 98305-98307
Backup superblock at 163840, Group descriptors at 163841-163843
Backup superblock at 229376, Group descriptors at 229377-229379
Backup superblock at 294912, Group descriptors at 294913-294915
Backup superblock at 819200, Group descriptors at 819201-819203
Backup superblock at 884736, Group descriptors at 884737-884739
Backup superblock at 1605632, Group descriptors at 1605633-1605635
Backup superblock at 2654208, Group descriptors at 2654209-2654211
Backup superblock at 4096000, Group descriptors at 4096001-4096003
Backup superblock at 7962624, Group descriptors at 7962625-7962627