Hi,

This machine is a Virtual machines on VMWARE ESX. This guest OS is not strating up after a POWER CRASH to the server. Its just straight away going to the following message on the black screen.

Kernal Panic - Not syncing : VFS: unable to mount root fs on unknown-block (0,0)

The OS is CentOS 5.5 64 bit.

Its a live web server & I am trying to make it up since yesterday without sleep but no luck!!

I booted up from an ISOimage to the rescue mode, but quite not sure what to do.

Please assist me to resolve the problem.

Thank you inadvance.

That usually means it can't find a root file system.
When I've had that, it has always been caused by disks being "re-numbered" - that is, disks are recognised in a different order.
Like this:
Normally, sda is 80 GB Western Digital, sdb is 120 GB Seagate.
But then sometimes it happens that system (we're talking bootup/BIOS/grub_legacy here, not the OS!) recognises Seagate as /dev/sda and WD 80GB as /dev/sdb and so the root file system is not where it's supposed to be.
Now you're running ESX, don't know if this is applicable - only "disks" applied by ESX are handled by the guest.
Could you please return with info about your setup, exactly what hardware is allocated to your CentOS guest.
Unfortunately, a power failure might - in the worst case - ruin your drive.
Let's just hope that hasn't happened!

Hi Thank you for the reply.
I have alocated 256GB space for the this guest OS.
When I boot the guset OS in Linux rescue mode & did a
df

and attached the screen dump.

Thanks

Attached Thumbnails