resize2fs: Either the superblock or the partition table is likely to be corrupt!

[malat]

Hi there,

  I was doing an extremely simple task: shrink my home partition /
resize my root partition.

Steps:

# df -h
  According to df, /home is 670G and / is 5.6G, so I decide to remove
20G from one to move it to the other.

# umount /home
# resize2fs /dev/mapper/gotlib-home 650G
... do some e2fsck dance
# lvreduce -L-20G /dev/mapper/gotlib-home
# mount /home

# lvextend -L+20G /dev/mapper/gotlib-root

Go get my debian CD installer, reboot, go to graphical rescue mode,
click , click, click, mount /home to run a shell into, then:

# resize2fs /dev/mapper/gotlib-root

So far everything seems to be going very well...

And then that's where I start crying, because on the next reboot, I am
asked to enter in maintenance mode:

# e2fsck -f /dev/mapper/gotlib-home
e2fsck 1.41.3 (12-Oct-2008)
The filesystem size (according to the superblock) is 178399232 blocks
The physical size of the device is 173156352 blocks
Either the superblock or the partition table is likely to be corrupt!
Abort<y>? yes

I tried to force :

# resize2fs -f /dev/mapper/gotlib-home

But I really do not know what I am doing, any help at this point will
be very appreciated !

Thanks,
--
Mathieu


Random info, from current workstation:
# lvdisplay
  --- Logical volume ---
  LV Name                /dev/gotlib/root
  VG Name                gotlib
  LV UUID                FnEtLa-ckzZ-R4V9-K7iV-nEKA-DqFE-Fltq5w
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                26.52 GB
  Current LE             6788
  Segments               2
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           254:0
  --- Logical volume ---
  LV Name                /dev/gotlib/home
  VG Name                gotlib
  LV UUID                9elvQJ-afoe-xw1S-AccD-0ZkM-wXR4-shhIkN
  LV Write Access        read/write
  LV Status              available
  # open                 0
  LV Size                660.54 GB
  Current LE             169098
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           254:2

# vgdisplay
  --- Volume group ---
  VG Name               gotlib
  System ID
  Format                lvm2
  Metadata Areas        1
  Metadata Sequence No  6
  VG Access             read/write
  VG Status             resizable
  MAX LV                0
  Cur LV                3
  Open LV               2
  Max PV                0
  Cur PV                1
  Act PV                1
  VG Size               698.39 GB
  PE Size               4.00 MB
  Total PE              178789
  Alloc PE / Size       178789 / 698.39 GB
  Free  PE / Size       0 / 0
  VG UUID               E0vONq-XIr0-fKHf-M6j9-xa4Q-S1AD-6vtyuf


# lvmdiskscan
  /dev/ram0  [       64.00 MB]
  /dev/root  [       26.52 GB]
  /dev/ram1  [       64.00 MB]
  /dev/dm-1  [       11.34 GB]
  /dev/ram2  [       64.00 MB]
  /dev/dm-2  [      660.54 GB]
  /dev/ram3  [       64.00 MB]
  /dev/ram4  [       64.00 MB]
  /dev/ram5  [       64.00 MB]
  /dev/ram6  [       64.00 MB]
  /dev/ram7  [       64.00 MB]
  /dev/ram8  [       64.00 MB]
  /dev/ram9  [       64.00 MB]
  /dev/ram10 [       64.00 MB]
  /dev/ram11 [       64.00 MB]
  /dev/ram12 [       64.00 MB]
  /dev/ram13 [       64.00 MB]
  /dev/ram14 [       64.00 MB]
  /dev/ram15 [       64.00 MB]
  /dev/sdc1  [      243.14 MB]
  /dev/sdc2  [      698.40 GB] LVM physical volume
  1 disk
  19 partitions
  0 LVM physical volume whole disks
  1 LVM physical volume


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[Boyd Stephen Smith Jr.-3]

In <bf0c3b3f0907070259u4ae4a1a4rf80e644dc55bf46e@...>, Mathieu
Malaterre wrote:

># df -h
>  According to df, /home is 670G and / is 5.6G, so I decide to remove
>20G from one to move it to the other.
>
># resize2fs /dev/mapper/gotlib-home 650G
>... do some e2fsck dance
># lvreduce -L-20G /dev/mapper/gotlib-home
>
># e2fsck -f /dev/mapper/gotlib-home
>e2fsck 1.41.3 (12-Oct-2008)
>The filesystem size (according to the superblock) is 178399232 blocks
>The physical size of the device is 173156352 blocks
>Either the superblock or the partition table is likely to be corrupt!
>Abort<y>? yes

You must have gotten bitten by some GiB vs. GB issue or something like that.

You've probably lost data at this point.

I'm not sure what the best recovery plan is.  If you haven't resized the
filesystem on /dev/mapper/gotlib-root, you may be able to use vgimport to
restore your old LVM layout, check your filesystems, and retry with more
conservative numbers.
--
Boyd Stephen Smith Jr.           ,= ,-_-. =.
bss@...             ((_/)o o(\_))
ICQ: 514984 YM/AIM: DaTwinkDaddy `-'(. .)`-'
http://iguanasuicide.net/            \_/

[malat]

On Tue, Jul 7, 2009 at 5:30 PM, Boyd Stephen Smith
Jr.<bss@...> wrote:

> In <bf0c3b3f0907070259u4ae4a1a4rf80e644dc55bf46e@...>, Mathieu
> Malaterre wrote:
>># df -h
>>  According to df, /home is 670G and / is 5.6G, so I decide to remove
>>20G from one to move it to the other.
>>
>># resize2fs /dev/mapper/gotlib-home 650G
>>... do some e2fsck dance
>># lvreduce -L-20G /dev/mapper/gotlib-home
>>
>># e2fsck -f /dev/mapper/gotlib-home
>>e2fsck 1.41.3 (12-Oct-2008)
>>The filesystem size (according to the superblock) is 178399232 blocks
>>The physical size of the device is 173156352 blocks
>>Either the superblock or the partition table is likely to be corrupt!
>>Abort<y>? yes
>
> You must have gotten bitten by some GiB vs. GB issue or something like that.
>
> You've probably lost data at this point.
>
> I'm not sure what the best recovery plan is.  If you haven't resized the
> filesystem on /dev/mapper/gotlib-root, you may be able to use vgimport to
> restore your old LVM layout, check your filesystems, and retry with more
> conservative numbers.

I gave up quickly after sending my first email, simply because I could
mount /home (for some reason it worked out nicely). I backup
everything needed and simply reinstall everything from scratch using
my debian installer CD.

As a side note, it took quite a few steps to setup LVM + a larger /.
By default / is only ~6G, who in the world can live with that when my
/home is 650G ? Anyway system seems to be fine now.

Thanks anyway,
--
Mathieu


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[Boyd Stephen Smith Jr.-3]

In Wednesday 08 July 2009, you wrote:
>As a side note, it took quite a few steps to setup LVM + a larger /.
>By default / is only ~6G, who in the world can live with that when my
>/home is 650G ? Anyway system seems to be fine now.

My desktop has a / that is 1GiB, but that's far too large, because /usr,
/opt, /srv, /var, and /tmp (in addition to /home) are all separate
filesystems.

My VPSes don't use more than 5GiB in / and they don't even have /home as a
separate file system.

I do tend to agree that, for a desktop, the file system holding /usr should
be closer to 10GB than 6GB.
--
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bss@...             ((_/)o o(\_))
ICQ: 514984 YM/AIM: DaTwinkDaddy `-'(. .)`-'
http://iguanasuicide.net/            \_/

[Miles Bader-2]

"Boyd Stephen Smith Jr." <bss@...> writes:

>>As a side note, it took quite a few steps to setup LVM + a larger /.
>>By default / is only ~6G, who in the world can live with that when my
>>/home is 650G ? Anyway system seems to be fine now.
>
> My desktop has a / that is 1GiB, but that's far too large, because /usr,
> /opt, /srv, /var, and /tmp (in addition to /home) are all separate
> filesystems.
>
> My VPSes don't use more than 5GiB in / and they don't even have /home as a
> separate file system.
>
> I do tend to agree that, for a desktop, the file system holding /usr should
> be closer to 10GB than 6GB.

Hmm, my / is 290MB, though /tmp, /var, /boot, and /usr are all separate
partitions.

290MB isn't that bad, but there's little room for errors like the recent
bloated kernel packages (now fixed), and the way Gnome used to put tons
of silly crap in /etc (now fixed as well).

Maybe 5-600MB on a separate-partition system would be a good size, not
insane, but some breathing room...

[My _previous_ box had only 150MB in /, and that was too little, I
couldn't even use pre-packaged debian kernels because they're too
bloated with lots of drivers.]

-Miles

--
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are true and our happiness is assured.


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[malat]

On Thu, Jul 9, 2009 at 3:23 AM, Miles Bader<miles@...> wrote:

> "Boyd Stephen Smith Jr." <bss@...> writes:
>>>As a side note, it took quite a few steps to setup LVM + a larger /.
>>>By default / is only ~6G, who in the world can live with that when my
>>>/home is 650G ? Anyway system seems to be fine now.
>>
>> My desktop has a / that is 1GiB, but that's far too large, because /usr,
>> /opt, /srv, /var, and /tmp (in addition to /home) are all separate
>> filesystems.
>>
>> My VPSes don't use more than 5GiB in / and they don't even have /home as a
>> separate file system.
>>
>> I do tend to agree that, for a desktop, the file system holding /usr should
>> be closer to 10GB than 6GB.
>
> Hmm, my / is 290MB, though /tmp, /var, /boot, and /usr are all separate
> partitions.

I *obviously* meant / in a two partitions system (/ and /home). The
only one growing is indeed /usr and 290MB for /usr is way too little.

--
Mathieu


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[Ron Johnson]

On 2009-07-08 20:23, Miles Bader wrote:
[snip]
>
> Hmm, my / is 290MB, though /tmp, /var, /boot, and /usr are all separate
> partitions.

*Why*?  IOW, what benefit do you derive in 2009 (as opposed to 1989,
when disks weren't always large enough to hold it all) from
splitting these out?

--
Scooty Puff, Sr
The Doom-Bringer


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[Mark Allums]

Ron Johnson wrote:

> On 2009-07-08 20:23, Miles Bader wrote:
> [snip]
>>
>> Hmm, my / is 290MB, though /tmp, /var, /boot, and /usr are all separate
>> partitions.
>
> *Why*?  IOW, what benefit do you derive in 2009 (as opposed to 1989,
> when disks weren't always large enough to hold it all) from splitting
> these out?
>

Protection by isolaton, partly.

Mark Allums


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[Don Quixote de la Mancha]

On Sun, Jul 19, 2009 at 8:31 PM, Mark Allums<mark@...> wrote:
> Protection by isolaton, partly.

I do the same thing.

Maybe it's just superstition, but it's fairly rare to lose a whole
hard drive, but fairly common to corrupt a filesystem.

Such corruption usually happens when you (intentionally) write to a
filesystem.  It could happen otherwise, because of some wildly buggy
kernel code writing outside the proper partition, but I would expect
that to be rare.

So if you have separate filesystems, /tmp, /var and /home are likely
to get corrupted, but /boot and / aren't so likely.  In the event of
this kind of corruption, you should still be able to boot.

Don Quixote
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[Manoj Srivastava-2]

On Sun, Jul 19 2009, Ron Johnson wrote:

> On 2009-07-08 20:23, Miles Bader wrote:
> [snip]
>>
>> Hmm, my / is 290MB, though /tmp, /var, /boot, and /usr are all separate
>> partitions.
>
> *Why*?  IOW, what benefit do you derive in 2009 (as opposed to 1989,
> when disks weren't always large enough to hold it all) from splitting
> these out?

        Security?

/dev/sdb2 / ext3 noatime,errors=remount-ro 0 1
/dev/sda1 /boot ext3 noatime,rw,defaults,noauto 0 2
/dev/mapper/anzu_main-usr_lv /usr ext3 noatime,ro,defaults 0 2
/dev/mapper/anzu_main-home_lv /home ext3 noatime,rw,nosuid,nodev 0 2
/dev/mapper/anzu_main-ulocal_lv /usr/local ext3 noatime,rw,nosuid,nodev 0 2
/dev/mapper/anzu_main-var_lv /var ext3 noatime,rw,nosuid               0 2
/dev/mapper/anzu_main-spool_lv /var/spool ext3 noatime,rw,nosuid,nodev 0 2

        Hmm. I had a chroot at some point in /var -- which is why it has
 no nodev. Time to change.

        manoj
--
It's the theory of Jess Birnbaum, of Time magazine, that women with bad
legs should stick to long skirts because they cover a multitude of shins.
Manoj Srivastava <srivasta@...> <http://www.golden-gryphon.com/>  
1024D/BF24424C print 4966 F272 D093 B493 410B  924B 21BA DABB BF24 424C


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[Ron Johnson]

On 2009-07-20 21:29, Manoj Srivastava wrote:

> On Sun, Jul 19 2009, Ron Johnson wrote:
>
>> On 2009-07-08 20:23, Miles Bader wrote:
>> [snip]
>>> Hmm, my / is 290MB, though /tmp, /var, /boot, and /usr are all separate
>>> partitions.
>> *Why*?  IOW, what benefit do you derive in 2009 (as opposed to 1989,
>> when disks weren't always large enough to hold it all) from splitting
>> these out?
>
>         Security?
>
> /dev/sdb2 / ext3 noatime,errors=remount-ro 0 1

Why device names instead of labels or UUIDs?

> /dev/sda1 /boot ext3 noatime,rw,defaults,noauto 0 2

noauto?????

> /dev/mapper/anzu_main-usr_lv /usr ext3 noatime,ro,defaults 0 2

I understand why this is ro; why then is /boot rw?

> /dev/mapper/anzu_main-home_lv /home ext3 noatime,rw,nosuid,nodev 0 2

What does nodev mean?  (My google fu must be lacking.)  Is "Do not
interpret character or block special devices on the file system."
just extra security so that a rogue app doesn't try to create a
device file anywhere but /dev?

> /dev/mapper/anzu_main-ulocal_lv /usr/local ext3 noatime,rw,nosuid,nodev 0 2
> /dev/mapper/anzu_main-var_lv /var ext3 noatime,rw,nosuid               0 2
> /dev/mapper/anzu_main-spool_lv /var/spool ext3 noatime,rw,nosuid,nodev 0 2

Seems to me that this whole exercise is to ensure that /dev is in
it's own partition.

--
Scooty Puff, Sr
The Doom-Bringer


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[Sven Joachim]

On 2009-07-21 05:50 +0200, Ron Johnson wrote:

> On 2009-07-20 21:29, Manoj Srivastava wrote:
>
>> /dev/sda1 /boot ext3 noatime,rw,defaults,noauto 0 2
>
> noauto?????

There is no need to mount /boot unless you install new kernels or update
your bootloader configuration.  Many people prefer to mount it
read-only, though.

>> /dev/mapper/anzu_main-usr_lv /usr ext3 noatime,ro,defaults 0 2
>
> I understand why this is ro; why then is /boot rw?

As I said, Manoj probably only mounts /boot to install new kernels, and
then he wants to write to it.

>> /dev/mapper/anzu_main-home_lv /home ext3 noatime,rw,nosuid,nodev 0 2
>
> What does nodev mean?  (My google fu must be lacking.)  Is "Do not
> interpret character or block special devices on the file system." just
> extra security so that a rogue app doesn't try to create a device file
> anywhere but /dev?

It does not prevent _creating_ device files, but it prevent _accessing_
them and the underlying hardware.

>> /dev/mapper/anzu_main-ulocal_lv /usr/local ext3 noatime,rw,nosuid,nodev 0 2
>> /dev/mapper/anzu_main-var_lv /var ext3 noatime,rw,nosuid               0 2
>> /dev/mapper/anzu_main-spool_lv /var/spool ext3 noatime,rw,nosuid,nodev 0 2
>
> Seems to me that this whole exercise is to ensure that /dev is in it's
> own partition.

Hardly, /dev is always on a tmpfs these days.  Unless you make your life
hard by not using udev, that is.

Sven


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[Ron Johnson]

On 2009-07-21 00:21, Sven Joachim wrote:
> On 2009-07-21 05:50 +0200, Ron Johnson wrote:
>
>> On 2009-07-20 21:29, Manoj Srivastava wrote:
>>
>>> /dev/sda1 /boot ext3 noatime,rw,defaults,noauto 0 2
>> noauto?????
>
> There is no need to mount /boot unless you install new kernels or update
> your bootloader configuration.

Very interesting.

>                                 Many people prefer to mount it
> read-only, though.
>
>>> /dev/mapper/anzu_main-usr_lv /usr ext3 noatime,ro,defaults 0 2
>> I understand why this is ro; why then is /boot rw?
>
> As I said, Manoj probably only mounts /boot to install new kernels, and
> then he wants to write to it.
>
>>> /dev/mapper/anzu_main-home_lv /home ext3 noatime,rw,nosuid,nodev 0 2
>> What does nodev mean?  (My google fu must be lacking.)  Is "Do not
>> interpret character or block special devices on the file system." just
>> extra security so that a rogue app doesn't try to create a device file
>> anywhere but /dev?
>
> It does not prevent _creating_ device files, but it prevent _accessing_
> them and the underlying hardware.

Guess I'll be adding that to /home's fstab entry...

>>> /dev/mapper/anzu_main-ulocal_lv /usr/local ext3 noatime,rw,nosuid,nodev 0 2
>>> /dev/mapper/anzu_main-var_lv /var ext3 noatime,rw,nosuid               0 2
>>> /dev/mapper/anzu_main-spool_lv /var/spool ext3 noatime,rw,nosuid,nodev 0 2
>> Seems to me that this whole exercise is to ensure that /dev is in it's
>> own partition.
>
> Hardly, /dev is always on a tmpfs these days.  Unless you make your life
> hard by not using udev, that is.

Then still I don't see the real gain to separating /usr and
/usr/local into their own partitions.

--
Scooty Puff, Sr
The Doom-Bringer


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[Siggy Brentrup-4]

On Sun, Jul 19, 2009 at 20:02 -0500, Ron Johnson wrote:
> On 2009-07-08 20:23, Miles Bader wrote:
> [snip]
> >
> >Hmm, my / is 290MB, though /tmp, /var, /boot, and /usr are all separate
> >partitions.
>
> *Why*?  IOW, what benefit do you derive in 2009 (as opposed to 1989,
> when disks weren't always large enough to hold it all) from
> splitting these out?

Not that abundance of partitions but even now it does make sense to
mount / ro except for /var and /tmp; only for maintainance / must be
remounted rw.

Regs
 Siggy
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or:                    bsb-at-psycho-dot-i21k-dot-de

[Johannes Wiedersich]

Ron Johnson wrote:
> Then still I don't see the real gain to separating /usr and /usr/local
> into their own partitions.

Just my humble guesswork: the same reasons as to why have /home on a
separate partition. /usr/local is the 'home' of custom software. ;-)

Johannes



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[Ron Johnson]

On 2009-07-21 05:45, Johannes Wiedersich wrote:
> Ron Johnson wrote:
>> Then still I don't see the real gain to separating /usr and /usr/local
>> into their own partitions.
>
> Just my humble guesswork: the same reasons as to why have /home on a
> separate partition. /usr/local is the 'home' of custom software. ;-)

IOW, very dynamic?  Makes sense, for a certain class of users.

--
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The Doom-Bringer


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[Boyd Stephen Smith Jr.-3]

In <4A655762.6020602@...>, Ron Johnson wrote:
>Then still I don't see the real gain to separating /usr and
>/usr/local into their own partitions.

/usr is managed by the distribution I have installed currently.
/usr/local is managed by me, and moves with me when I change distributions,
like /home.

Currently, I only really use /usr/local/share/doc, though.
--
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bss@...             ((_/)o o(\_))
ICQ: 514984 YM/AIM: DaTwinkDaddy `-'(. .)`-'
http://iguanasuicide.net/            \_/

[Ron Johnson]

On 2009-07-21 11:51, Boyd Stephen Smith Jr. wrote:
> In <4A655762.6020602@...>, Ron Johnson wrote:
>> Then still I don't see the real gain to separating /usr and
>> /usr/local into their own partitions.
>
> /usr is managed by the distribution I have installed currently.
> /usr/local is managed by me, and moves with me when I change distributions,
> like /home.

I just back it and then restore to new system... ;)

--
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The Doom-Bringer


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[Boyd Stephen Smith Jr.-3]

In <4A665BF5.2090505@...>, Ron Johnson wrote:

>On 2009-07-21 11:51, Boyd Stephen Smith Jr. wrote:
>> In <4A655762.6020602@...>, Ron Johnson wrote:
>>> Then still I don't see the real gain to separating /usr and
>>> /usr/local into their own partitions.
>>
>> /usr is managed by the distribution I have installed currently.
>> /usr/local is managed by me, and moves with me when I change
>> distributions, like /home.
>
>I just back it and then restore to new system... ;)

I don't have to wait for data to transfer or put additional stress on the
hardware with reads/writes.  My /usr/local is < 1GiB, so it doesn't matter
much.  /home stays much bigger, though.
--
Boyd Stephen Smith Jr.           ,= ,-_-. =.
bss@...             ((_/)o o(\_))
ICQ: 514984 YM/AIM: DaTwinkDaddy `-'(. .)`-'
http://iguanasuicide.net/            \_/

[Manoj Srivastava-2]

On Mon, Jul 20 2009, Ron Johnson wrote:

> On 2009-07-20 21:29, Manoj Srivastava wrote:
>> On Sun, Jul 19 2009, Ron Johnson wrote:
>>
>>> On 2009-07-08 20:23, Miles Bader wrote:
>>> [snip]
>>>> Hmm, my / is 290MB, though /tmp, /var, /boot, and /usr are all separate
>>>> partitions.
>>> *Why*?  IOW, what benefit do you derive in 2009 (as opposed to 1989,
>>> when disks weren't always large enough to hold it all) from splitting
>>> these out?
>>
>>         Security?
>>
>> /dev/sdb2 / ext3 noatime,errors=remount-ro 0 1
>
> Why device names instead of labels or UUIDs?

        *Shrug*. Been a while, and it has been working form me for
 years. Why change?

>> /dev/sda1 /boot ext3 noatime,rw,defaults,noauto 0 2
>
> noauto?????


        Who the hell wants the braindead initramfs mucking around with a
 working boot system? It also ensures that I have to be actively
 thinking about modifying my boot process before changes happen.


>> /dev/mapper/anzu_main-usr_lv /usr ext3 noatime,ro,defaults 0 2
>
> I understand why this is ro; why then is /boot rw?

        Cause it is never mounted.

>> /dev/mapper/anzu_main-home_lv /home ext3 noatime,rw,nosuid,nodev 0 2
>
> What does nodev mean?  (My google fu must be lacking.)  Is "Do not
> interpret character or block special devices on the file system." just
> extra security so that a rogue app doesn't try to create a device file
> anywhere but /dev?

        So no one can create a device or a block char file elsewhere in
 the file system, yes.


>> /dev/mapper/anzu_main-ulocal_lv /usr/local ext3 noatime,rw,nosuid,nodev 0 2
>> /dev/mapper/anzu_main-var_lv /var ext3 noatime,rw,nosuid               0 2
>> /dev/mapper/anzu_main-spool_lv /var/spool ext3 noatime,rw,nosuid,nodev 0 2
>
> Seems to me that this whole exercise is to ensure that /dev is in it's
> own partition.

        Layered security is always better than waiting for the silver
 bullet all secure mechanism. It is all about increasing the work factor
 for Mallory.

        manoj
--
All is well that ends well. John Heywood
Manoj Srivastava <srivasta@...> <http://www.golden-gryphon.com/>  
1024D/BF24424C print 4966 F272 D093 B493 410B  924B 21BA DABB BF24 424C


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