Re: [CentOS] mount the wrong device after system recovery

At Tue, 8 Feb 2011 16:31:32 -0500 CentOS mailing list centos@centos.org wrote:

My grub.conf is pointing to sdb1 for /. I've corrected to use /dev/vg0/lv1. But after rebooting, I am getting the same error. I guess I need to rebuild initrd.img file. How do I rebuild that file?

The best way to do it *right* is to boot with a rescue system (such as the installer CD/DVD). You need to make sure it properly mounts the necessary file systems, specificly /dev/vg0/lv1 as /sysroot, whatever you are using for /boot to /sysroot/boot (/boot can't be in the LVM volume group -- grub cannot deal with that!), then make sute /proc, /sys, and /dev are mount --bind'd to /sysroot/proc, /sysroot/sys, and /sysroot/dev. Then you will chroot to /sysroot and issue a command like:

mkinitrd -f /boot/initrd-2.6.18-194.32.1.el5.img 2.6.18-194.32.1.el5

(replace '2.6.18-194.32.1.el5' with the proper kernel version you will be booting from -- 2.6.18-194.32.1.el5 is the latest CentOS 5.5 kernel).

exit and reboot.

Thanks,

• xinhuan

-----Original Message----- From: centos-bounces@centos.org [mailto:centos-bounces@centos.org] On Behalf Of Robert Heller Sent: Tuesday, February 08, 2011 2:59 PM To: CentOS mailing list Cc: CentOS mailing list Subject: Re: [CentOS] mount the wrong device after system recovery

At Tue, 8 Feb 2011 13:51:32 -0500 CentOS mailing list centos@centos.org wrote:

...

Content-Class: urn:content-classes:message

Hi,

I am recovering a CentOS 5.4 system. I've copied all partitions into

the

...

recovery system. I've installed grub boot loader. However, the

original

...

system is using /dev/sdb1 for root (/), while the recovery system is using LVM (/dev/vg0/lv1) for root (/). When recovery system boots, I

got

...

the panic error:

•     Mounting /dev/sdb1 on /sysroot
  
  

•     Mount: mounting /dev/sdb1 on /sysroot failed: No such file
  

or

...

directory

•     Mount: mounting /dev on /sysroot/dev failed: No such file or
  

directory

•     * switching / to /sysroot
  
  

•     Switch_root: bad newroot /sysroot
  
  

•     Kernel panic - not syncing: Attempted to kill init!
  
  
  
  

I've changed the recovery system fstab to use the correct devices. I deleted recovery system etc/lvm/cache/.cache file. But it still

doesn't

...

work. What am I missing?

You need to rebuild the initrd and make sure the grub.conf file is up-to-date (has the right thing for the root parameter).

...

Thanks,

•      xinhuan
  
  

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