[CentOS] dd disk will not boot - can't find /dev/root

Wed Dec 14 15:56:49 UTC 2011
Joseph Spenner <joseph85750 at yahoo.com>




Am 12.12.2011 17:01, schrieb Joseph Spenner:
> 
> ________________________________
>  From: Joseph Spenner <joseph85750 at yahoo.com>
> To: "centos at centos.org" <centos at centos.org> 
> Sent: Monday, December 12, 2011 8:51 AM
> Subject: [CentOS] dd disk will not boot - can't find /dev/root
>  
> OS= CentOS 5.4, 64bit.
> 
> I've always had great luck using dd to copy entire disks, and booting on other systems.  However, I'm having difficulty with a couple systems.  I boot using an install DVD so the OS disk is quiet, and dd to my target disk:
> 
> # dd if=/dev/sda of=/dev/sdb bs=1024k
> 
> /dev/sdb is the blank disk.  The disks are 2T.  After a few hours the operation is complete.  But when I try to boot the new disk on my other system, I get the following errors after the CentOS boot menu (it counts down to boot the default disk fine, then this error):
> 
>   (screen shot at   http://img214.imageshack.us/img214/645/centosbooterror.jpg   )
> 
> I've read posts regarding the /dev/root error, and they talk about rebuilding initrd.  I've tried some of the fixes mentioned, but have had no success.
> All I can think of is slightly different hardware on the new system where I'm trying to boot, but I'm not sure what the difference could be.
> They're both 64bit SuperMicro systems.
> 
> If anyone has any ideas, I'd love to hear.

boot from the rescue-cd and reinstall the kernel of the cloned system
or make a new initramdisk per hand - i guess the kernel is missing some
needed hardware-driver of the new computer in the initrd

=============
Thanks for the replies!
I booted the rescue-cd and reinstalled initrd from RPM.  That seemed to fix it.

It amazes me how complex the whole boot process needs to be.  Or why there doesn't exist a simple bootable CD to fix an incorrect or destroyed MBR /boot partition, based on what it can analyze and figure out.


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