fsck sanity check failed read of superblock failed

[Rafael Moran]

Hi all !

On a class d server with hpux 10.20, I got the following boot error:

vxfs: fsck sanity check failed
read of superblock on /dev/vgxxx/lvolxxx failed
cannot open device.

I tried to do a fsck manually but it says cannot open device. Also I cannot mount it by any way.
I searched on the docs and forums and I saw there is a way to recover the superblock with fsck -b but the fsck I got installed has not this option.

Does anyone know how to recover the superblock or any idea what I can do ?

Thank you all

[Volker Borowski · Accepted solution]

Hmm,

/etc/sbtab holds a list of alternate superblocks for hfs-filesystems, that can be fixed with "fsck -b16 ...." as block 16 usally holds the first copy of the superblock. But as far as I know, this is not valid for vxfs filesystems.

Are you sure that the filesystem you check is vxfs ? If it is a hfs filesystem on 10.20 you may need to override defaults like

fsck -F hfs -b 16 /dev/vg00/rlvolxx

If your root filesystem is accessible, check /etc/fstab and /etc/default/fs for the filesystemtype chosen by fsck.

Hope this helps
Volker

[Rafael Moran]

Hello Volker and thank you for your answer,

The filesystem is sure vxfs. The line on fstab is:

/dev/vgxxx/lvolxxx filesystemname vxfs rw,suid,delaylog,datainlog 0 2

On sbtab there is no mention to this filesystem
so I suppose there is no way no do the fsck -b

[Volker Borowski]

Hello Rafael,

please check "man fsck_vxfs" to see the filesystemspecific options that are applicable to fsck for vxfs filesystems.

May be you need to use "-o full".

Check /var/adm/syslog and "dmesg" first, to see if a disk is offline or any errors are reported.

If your are on contract with HP and have diagnostic tools installed, you can open a call to HP, and use the tools (you will require a password) to read the error logs of the disk in charge.

Hope this helps
Volker

[Bill Hassell]

Cannot open device is not the same as cannot read a specific block. I would suspect that there is corruption of the LVM information which means that LVM is unable to locate the lvol listed. You'll need to recover the lvol (and volume group) if necessary.

[Rafael Moran]

Thank you both,

Anything I try versus this disk all I obtain is "cannot open device" ( fbackup, dd ...)
I had a software consult opened since this morning and I had no solutions yet.
After checking it I found a dead hard-disk
so obviusly I will call hp to change it and recover from backup copy

Thanks again for your asistance