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#1 2007-07-21 14:30:16

Newnux
Member
Registered: 2007-06-13
Posts: 59

[Solved] The superblock could not be read

I run the ext2 driver on Windows, which automatically mounts all ext3 partitions that I have.  I just switched to Windows to do something, and upon coming back to Arch, I had this problem since bootup.  I haven't had this problem before, and I hadn't even touched anything in the problem drive.

I started up and was greeted by the following error:

fsck 1.40 (29-Jun-2007)
e2fsck 1.40 (29-Jun-2007)
fsck.ext3: No such file or directory while trying to open /dev/sdb1

The superblock could not be read or does not describe a correct ext2
filesystem.  If the device is valid and it really contains an ext2
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
    e2fsck -b 8193 <device>

Well, it may not be exactly the same, but it was similar.  I just grabbed this after running fsck on the drive.  Because I couldn't get to login or anything, I changed my fstab entry:

#/dev/sdb1    /mnt/sto    ext3    auto,rw,user        0    1 # original
/dev/sdb1    /mnt/sto    ext3    rw,user        0    0 #new

This allowed me to login as normal without any problems, other than that /dev/sdb1 isn't being recognised.

mount: special device /dev/sdb1 does not exist

e2fsck outputs the same error as fsck; all commands say either bad superblock or device not found.

Any help would be appreciated, or even ideas on how this came about in the first place.  I can't really afford to lose the data on this drive.  I'd even be grateful if someone could help in the formatting of my posts, as I don't find they're very clear.

Thanks.

Last edited by Newnux (2007-07-21 19:34:13)

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#2 2007-07-21 15:36:59

ataraxia
Member
From: Pittsburgh
Registered: 2007-05-06
Posts: 1,537

Re: [Solved] The superblock could not be read

Does anything else on this disk work? (If there is anything else)

What do /var/log/messages and the output from 'dmesg' say about this disk? (Especially, what does the kernel say about it during bootup?)

Does plain '/dev/sdb' exist (without the '1')?

From here, it looks like a failed disk, or a loose cable.

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#3 2007-07-21 15:56:14

Newnux
Member
Registered: 2007-06-13
Posts: 59

Re: [Solved] The superblock could not be read

Appreciate the reply, thanks.

I'm not totally sure how to carry out what you asked for, but here's what I managed.  Let me know if I missed something.  Also, there is only one partition on the disk: /sdb1

dmesg | grep sdb:

SCSI device sdb: 398297088 512-byte hdwr sectors (203928 MB)
sdb: Write Protect is off
sdb: Mode Sense: 00 3a 00 00
SCSI device sdb: write cache: enabled, read cache: enabled, doesn't support DPO or FUA
SCSI device sdb: 398297088 512-byte hdwr sectors (203928 MB)
sdb: Write Protect is off
sdb: Mode Sense: 00 3a 00 00
SCSI device sdb: write cache: enabled, read cache: enabled, doesn't support DPO or FUA
 sdb: unknown partition table
sd 0:0:1:0: Attached scsi disk sdb
VFS: Can't find ext3 filesystem on dev sdb.

There doesn't seem to be a file called /var/log/messages, but there were a couple called /var/log/messages.log(.1-4) which didn't contain anything.

I don't know how to check if something "exists" but I tried mounting /dev/sdb with sudo mount -t ext3 /dev/sdb /mnt/tmp and it returned:

mount: wrong fs type, bad option, bad superblock on /dev/sdb,
       missing codepage or other error
       In some cases useful info is found in syslog - try
       dmesg | tail  or so

Other than that, I can't really think it would be a loose cable because it was working just fine until I switched to Windows and back.  No clue if it was working in Windows, as I didn't really look at the disk, but it always has in the past.

Update: I poked around in qtparted and /dev/sdb is showing as a disk.  The only "Partition" it shows is named "Partition table" and has the Status "Empty".

Update 2: I ran testdisk to "Analyse current partition structure and search for lost partitions."  The search completed without problems, but no partitions were found.

Update 3: I had intel partitions selected (or some such) in the previous run of testdisk, but I tried searching for unpartitioned... partitions this time.  Hope I'm making some kind of sense..  Anyway, it's going ridiculously slow, but it quickly came up with the following line:

  HFS                     28  93 29 22477569 163 13  324447696 [T85^_ZI\Ro^R^Q^S'"

Update 4: Stopped testdisk as I don't really have the time to wait that long, and doubted it would find anything else.  It displayed the following:

Disk /dev/sdb - 203 GB / 189 GiB - CHS 24792 255 63

The harddisk (203 GB / 189 GiB) seems too small! (< 184 TB / 168 TiB)
Check the harddisk size: HD jumpers settings, BIOS detection...

The following partition can't be recovered:
     Partition               Start        End    Size in sectors
D HFS                     28  93 29 22477569 163 13  324447696 [T85^_ZI\Ro^R^Q^S'"w^Q~B~N
^YN7]









[ Continue ]

HFS, 184 TB / 168 TiB

Something is obviously messed up.  Worth mentioning that the drive had ~1-5gb left and was ~180gb.  Should I just format it to ext3 and recover all the data?  I've done this with NTFS partitions in Windows before, but I'm not sure of a solid procedure in Linux.

Last edited by Newnux (2007-07-21 16:35:23)

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#4 2007-07-21 18:38:35

Newnux
Member
Registered: 2007-06-13
Posts: 59

Re: [Solved] The superblock could not be read

fdisk -l

Disk /dev/sda: 81.9 GB, 81964302336 bytes
255 heads, 63 sectors/track, 9964 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1        5737    46082421    7  HPFS/NTFS
/dev/sda2            5738        5986     2000092+  83  Linux
/dev/sda3            5987        6837     6835657+  83  Linux
/dev/sda4            6838        9964    25117627+  83  Linux

Disk /dev/sdb: 203.9 GB, 203928109056 bytes
255 heads, 63 sectors/track, 24792 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/sdb doesn't contain a valid partition table

Even as a newbie, this seems pretty obvious that the partition table is messed up.  I just have no idea where to go from there, and am pretty desperate waiting for some sort of help on the subject.

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#5 2007-07-21 19:30:45

Newnux
Member
Registered: 2007-06-13
Posts: 59

Re: [Solved] The superblock could not be read

Okay, well it's not working.

Solution:  I opened up my case, pushed in the related IDE and molex cables, and started up.  I'm greeted by an fsck on the problem drive, and it's working perfectly.  Strange thing is, no cables were even remotely loose.  Anyway, I've now learnt to start with the obvious!

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#6 2007-07-21 22:00:20

ataraxia
Member
From: Pittsburgh
Registered: 2007-05-06
Posts: 1,537

Re: [Solved] The superblock could not be read

I'd start being suspicious about hardware now (the cable and the disk housing, mostly). And I'd back up all that data now, while it's working, in case it decides to stop doing so again suddenly.

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#7 2007-07-21 22:46:25

.:B:.
Forum Fellow
Registered: 2006-11-26
Posts: 5,819

Re: [Solved] The superblock could not be read

Did you do as the fsck.ext3 utility recommended: specify an alternate superblock? Add 8192 by the first, and you get the second (8193), add one more, and you got the third, and so on, and so on. You get the picture I suppose wink.


Got Leenucks? :: Arch: Power in simplicity :: Get Counted! Registered Linux User #392717 :: Blog thingy

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#8 2010-05-22 18:17:54

trusktr
Banned
From: .earth
Registered: 2010-02-18
Posts: 907
Website

Re: [Solved] The superblock could not be read

hey .:B:. i am also having the same message except i am booting from my one and only linux drive.

i get that same error message about the superblock thingie. But i'm not sure what to do!

Can you explain what you said exacly?

Did you do as the fsck.ext3 utility recommended: specify an alternate superblock? Add 8192 by the first, and you get the second (8193), add one more, and you got the third, and so on, and so on. You get the picture I suppose .

What does that do?

screen says this:

fsck 1.40 (29-Jun-2007)
e2fsck 1.40 (29-Jun-2007)
fsck.ext3: No such file or directory while trying to open /dev/sdb1

The superblock could not be read or does not describe a correct ext2
filesystem.  If the device is valid and it really contains an ext2
filesystem (and not swap or ufs or something else), then the superblock
is corrupt, and you might try running e2fsck with an alternate superblock:
    e2fsck -b 8193 <device>

Also, how exactly do i enter that last command?


joe@trusktr.io - joe at true skater dot io.

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#9 2011-10-05 01:44:11

scorchgeek
Member
Registered: 2011-10-05
Posts: 1

Re: [Solved] The superblock could not be read

This is a really old thread by now, but I just wanted to note that I came across it having the same problem and discovered that my issue was that the labels on my partitions had changed. I just dropped to root shell prompt and fixed the labels in /etc/fstab to match the partitions displayed by fdisk, and everything was fine.

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#10 2011-10-05 04:13:31

ngoonee
Forum Fellow
From: Between Thailand and Singapore
Registered: 2009-03-17
Posts: 6,790

Re: [Solved] The superblock could not be read

A necrobump of a necrobump, that's new.... please don't necrobump if at all possible, especially on a solved thread. Closing.


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