disappearing xfs partition

disappearing xfs partition

[Jeff Breidenbach]

I have no special reason to believe this is xfs specific, but
is it common for partitions to vanish from the face of the
earth, at least as far as mount is concerned? I usually mount
by UUID, but here's a sightly interesting transcript by drive
letters. If this is not xfs relevant, any suggestions where
to start digging?

This is a standard format XFS partition, created with an
xfsprogs that I compiled a couple weeks ago from a source
code download. Note that other xfs partitions are mounting
fine on the same machine.


-- after a fresh reboot ---

# cfdisk /dev/sde

    Name        Flags      Part Type  FS Type          [Label]        Size (MB)
 ------------------------------------------------------------------------------
    sde1                    Primary   Linux XFS                      1000202.28

# mount /dev/sde1 /mnt
mount: special device /dev/sde1 does not exist

# xfs_check /dev/sde1
/dev/sde1: No such file or directory

fatal error -- couldn't initialize XFS library

# fdisk /dev/sde

The number of cylinders for this disk is set to 121601.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
   (e.g., DOS FDISK, OS/2 FDISK)

Command (m for help): p

Disk /dev/sde: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x00000000

   Device Boot      Start         End      Blocks   Id  System
/dev/sde1               1      121601   976760001   83  Linux

# cat /proc/version
Linux version 2.6.24-8-server (buildd@yellow) (gcc version 4.2.3
(Ubuntu 4.2.3-1ubuntu2)) #1 SMP Thu Feb 14 20:42:20 UTC 2008

# dpkg -l xfsprogs
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Installed/Config-f/Unpacked/Failed-cfg/Half-inst/t-aWait/T-pend
|/ Err?=(none)/Hold/Reinst-required/X=both-problems (Status,Err: uppercase=bad)
||/ Name           Version        Description
+++-==============-==============-============================================
ii  xfsprogs       2.9.5-1        Utilities for managing the XFS filesystem

Re: disappearing xfs partition

[Justin Piszcz]

Looks like a udev problem or something is not making /dev/sde1? Have you 
tried a manual mknod of the device?

On Mon, 3 Mar 2008, Jeff Breidenbach wrote:

> I have no special reason to believe this is xfs specific, but
> is it common for partitions to vanish from the face of the
> earth, at least as far as mount is concerned? I usually mount
> by UUID, but here's a sightly interesting transcript by drive
> letters. If this is not xfs relevant, any suggestions where
> to start digging?
>
> This is a standard format XFS partition, created with an
> xfsprogs that I compiled a couple weeks ago from a source
> code download. Note that other xfs partitions are mounting
> fine on the same machine.
>
>
> -- after a fresh reboot ---
>
> # cfdisk /dev/sde
>
>    Name        Flags      Part Type  FS Type          [Label]        Size (MB)
> ------------------------------------------------------------------------------
>    sde1                    Primary   Linux XFS                      1000202.28
>
> # mount /dev/sde1 /mnt
> mount: special device /dev/sde1 does not exist
>
> # xfs_check /dev/sde1
> /dev/sde1: No such file or directory
>
> fatal error -- couldn't initialize XFS library
>
> # fdisk /dev/sde
>
> The number of cylinders for this disk is set to 121601.
> There is nothing wrong with that, but this is larger than 1024,
> and could in certain setups cause problems with:
> 1) software that runs at boot time (e.g., old versions of LILO)
> 2) booting and partitioning software from other OSs
>   (e.g., DOS FDISK, OS/2 FDISK)
>
> Command (m for help): p
>
> Disk /dev/sde: 1000.2 GB, 1000204886016 bytes
> 255 heads, 63 sectors/track, 121601 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
> Disk identifier: 0x00000000
>
>   Device Boot      Start         End      Blocks   Id  System
> /dev/sde1               1      121601   976760001   83  Linux
>
> # cat /proc/version
> Linux version 2.6.24-8-server (buildd@yellow) (gcc version 4.2.3
> (Ubuntu 4.2.3-1ubuntu2)) #1 SMP Thu Feb 14 20:42:20 UTC 2008
>
> # dpkg -l xfsprogs
> Desired=Unknown/Install/Remove/Purge/Hold
> | Status=Not/Installed/Config-f/Unpacked/Failed-cfg/Half-inst/t-aWait/T-pend
> |/ Err?=(none)/Hold/Reinst-required/X=both-problems (Status,Err: uppercase=bad)
> ||/ Name           Version        Description
> +++-==============-==============-============================================
> ii  xfsprogs       2.9.5-1        Utilities for managing the XFS filesystem
>
>

Re: disappearing xfs partition

[Eric Sandeen]

Justin Piszcz wrote:
> Looks like a udev problem or something is not making /dev/sde1? Have you 
> tried a manual mknod of the device?

but... it is not an xfs problem.  :)

(also check /proc/partitions for sde1...)

-Eric

Re: disappearing xfs partition

[Jeff Breidenbach]

On Mon, Mar 3, 2008 at 8:20 AM, Eric Sandeen <sandeen@sandeen.net> wrote:
> Justin Piszcz wrote:
>  > Looks like a udev problem or something is not making /dev/sde1? Have you
>  > tried a manual mknod of the device?

# mknod /dev/sde1 b 8 65

# mount /dev/sde1 /data2
mount: /dev/sde1 is not a valid block device

>  but... it is not an xfs problem.  :)

Sorry for posting.

>  (also check /proc/partitions for sde1...)

Not present.

# grep sde /proc/partitions
   8    64  976762584 sde

Re: disappearing xfs partition

[Josef 'Jeff' Sipek]

On Mon, Mar 03, 2008 at 05:14:38AM -0800, Jeff Breidenbach wrote:
...
> # dpkg -l xfsprogs
> Desired=Unknown/Install/Remove/Purge/Hold
> | Status=Not/Installed/Config-f/Unpacked/Failed-cfg/Half-inst/t-aWait/T-pend
> |/ Err?=(none)/Hold/Reinst-required/X=both-problems (Status,Err: uppercase=bad)
> ||/ Name           Version        Description
> +++-==============-==============-============================================
> ii  xfsprogs       2.9.5-1        Utilities for managing the XFS filesystem

As others have already pointed out, the problem you have is not with XFS,
but probably with udev.

You may want to upgrade your xfsprogs. Version 2.9.5 has a buggy mkfs (the
fs it makes uses only about 3/4 of the partition).

Josef 'Jeff' Sipek.

-- 
Computer Science is no more about computers than astronomy is about
telescopes.
		- Edsger Dijkstra

Re: disappearing xfs partition

[Jeff Breidenbach]

Following up and close out the topic, I got this comment from Eric.

>So parted has this bad habit of making partition tables that cannot
>actually be read from the disk, and poking the supposedly values
>directly into the kernel.  Then things work fine until reboot, at which
>time the partition table cannot be properly read.   Usually this turns
>into a truncated size due to an overflow....

I'd been using cfdisk and not parted, but that's apparently what
happened. Rewriting the partition table with cfdisk fixed everything
and allowed the partition to mount. At least for this boot.

Thanks all.

Re: disappearing xfs partition

[Martin Steigerwald]

Am Dienstag 04 März 2008 schrieb Jeff Breidenbach:
> Following up and close out the topic, I got this comment from Eric.
>
> >So parted has this bad habit of making partition tables that cannot
> >actually be read from the disk, and poking the supposedly values
> >directly into the kernel.  Then things work fine until reboot, at
> > which time the partition table cannot be properly read.   Usually
> > this turns into a truncated size due to an overflow....
>
> I'd been using cfdisk and not parted, but that's apparently what
> happened. Rewriting the partition table with cfdisk fixed everything
> and allowed the partition to mount. At least for this boot.

Hi Jan,

Its always a good idea to check whether the kernel reread the partition 
table after partitioning with

cat  /proc/partitions

If it doesn't have you can tell the kernel to do it manually:

blockdev --rereadpt /dev/sde

If that tells you something about device is busy or so you'd need to 
unmount partitions on it or reboot.

Ciao,
-- 
Martin 'Helios' Steigerwald - http://www.Lichtvoll.de
GPG: 03B0 0D6C 0040 0710 4AFA  B82F 991B EAAC A599 84C7