Comments on: Understanding UNIX / Linux filesystem Superblock

By: rakesh

rakesh — Tue, 13 Sep 2011 07:52:40 +0000

dude.. commands is dump2efs

u used dump2fs

By: saikumar

saikumar — Thu, 14 Jul 2011 03:59:53 +0000

is it possible to install linux in personal lappies? core2duo processor( dell laptop)…
is it possible even vmware workstation is installed in laptops….

By: sox

sox — Tue, 24 May 2011 01:37:57 +0000

what is meant by offset information in a filesystem?

By: Govindasamy C

Govindasamy C — Wed, 28 Jan 2009 05:25:18 +0000

Its working fine for me
sunil i think you did not give space after the command dumpe2fs

By: c

Mon, 24 Nov 2008 06:10:17 +0000

To Swapnil,

You have sparse_super mode so super block and backups are saved in groups 0,1,3^n,5^n,7^n (e.g. 0,1,3,5,7,9,25,27,…). If you take a look at mke2fs code, you’ll see these places where super blocks are saved.

p.s. this is a very late comment but just wanted to comment..

By: vivek

vivek — Fri, 18 Apr 2008 10:46:20 +0000

Use full path /sbin/dumpe2fs, you are logged in as regular user and /sbin and /usr/sbin not in PATH settings.

By: Sunil

Sunil — Fri, 18 Apr 2008 06:40:12 +0000

Hey this command id not working on my system…

[sunilv@lnx202-28 ~]$ dump2fs /u/sunilv | grep -i superblock
dump2fs: Command not found.

By: Swapnil

Swapnil — Fri, 31 Aug 2007 06:05:02 +0000

Hi Vivek,

I have a doubt as how many redundant backups of superblock are created in the file system ? Is it made on every block group or only on initial few block groups ?
In the filesystem that I created of size 128 MB with 16 block groups, when I run the dumpe2fs command on it, it gives the info on superblocks (These are not the exact wordings of the output ) :
primary superblock is present on block group 0,
back up superblock is present on block group 1, 3, 5, 7, 9.

Similarly for a file system with 256 MB size and 31 block groups, primary superblock is present on block group 0 and backups are present on block groups 1,3,5,7, and 9.

So my doubt is how does the file system how many backups of the superblock to be created ?
And the same doubt for block group descriptors as well. Block group descriptors are not present in each block group but only in the block groups where superblock is present.

Hoping for an earliest response.

Thanks,
Swapnil

By: bipul

bipul — Wed, 01 Aug 2007 08:14:22 +0000

Hello Unix Team
how are you

By: Kristian

Kristian — Sat, 05 May 2007 16:33:22 +0000

It should be mentioned that dumpe2fs only is for the ext2/ext3 file systems.

By: nixcraft

nixcraft — Wed, 31 May 2006 21:59:00 +0000

Opps pipe was missing, thanks for heads up.

Hmm it should give the output.

By: Anonymous

Anonymous — Wed, 31 May 2006 17:13:00 +0000

# dumpe2fs /dev/hda3grep -i superblock
above command is not running here |(pipe) is missing, anyway

I am getting different output as you mentioned
[root@sachan /root]# dumpe2fs /dev/hda1 | grep -i superblock
dumpe2fs 1.19, 13-Jul-2000 for EXT2 FS 0.5b, 95/08/09
[root@sachan /root]#