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After booting ubuntu 14.10 I got log output like this

[1377286.486802] EXT4-fs (sda2): unable to read superblock

I can login and use the machine but I guess something is wrong.

Some diagnostics using fdisk, dumpe2fs and e2fsck were made.

How bad is this and what should/can be done?

sudo fdisk -l

Disk /dev/sda: 16 GiB, 17179869184 bytes, 33554432 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x71f43c62

Device     Boot  Start      End  Sectors  Size Id Type
/dev/sda1  *      2048   499711   497664  243M 83 Linux
/dev/sda2       501758 33552383 33050626 15.8G  5 Extended
/dev/sda5       501760 33552383 33050624 15.8G 8e Linux LVM

Disk /dev/mapper/Ubuntu--vg-root: 11.8 GiB, 12624855040 bytes, 24657920 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk /dev/mapper/Ubuntu--vg-swap_1: 4 GiB, 4294967296 bytes, 8388608 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

sudo dumpe2fs /dev/sda2

dumpe2fs 1.42.10 (18-May-2014)
dumpe2fs: Attempt to read block from filesystem resulted in short read while trying to open /dev/sda2
Couldn't find valid filesystem superblock.

sudo e2fsck -f /dev/sda2

e2fsck 1.42.10 (18-May-2014)
e2fsck: Attempt to read block from filesystem resulted in short read while trying to open /dev/sda2

Could this be a zero-length partition?
user264230
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1 Answers1

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Well, yeah, you're trying to mount an extended partition, which is never going to end well -- there is no filesystem on that partition. What partition did you want to mount, instead?

womble
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  • Also he needs to activate logical volumes. – Mircea Vutcovici Sep 29 '15 at 22:52
  • There's no indication that the LVs aren't active. – womble Sep 29 '15 at 23:34
  • Do you mean that I got the log message because the system have tried to mount /dev/sda? My guess in that case is that /dev/sda5 only should be used. From where would such a wrong mount operation come from? Are there a script where I possibly could disable it? – user264230 Sep 30 '15 at 07:40
  • No, `/dev/sda5` shouldn't be used, because it's an LVM PV, not a filesystem. A wrong mount operation happens when the system is misconfigured. Whatever you misconfigured, undo that. – womble Sep 30 '15 at 08:41
  • I just installed Ubuntu 15.10 server on an ESXI host. The default configuration left me with the exact same situation. – Phillip Scott Givens Feb 19 '16 at 02:08