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%C2%A0%C2%A0 )
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.
Thanks!
________________________________ From: Joseph Spenner joseph85750@yahoo.com To: "centos@centos.org" centos@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%C2%A0%C2%A0 )
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.
Thanks! _______________________________________________
I just noticed the link didn't like my ( ). The clickable link is: http://img214.imageshack.us/img214/645/centosbooterror.jpg
Am 12.12.2011 17:01, schrieb Joseph Spenner:
From: Joseph Spenner joseph85750@yahoo.com To: "centos@centos.org" centos@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
Am 12.12.2011 17:01, schrieb Joseph Spenner:
From: Joseph Spenner joseph85750@yahoo.com To: "centos@centos.org" centos@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%C2%A0 )
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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On Wed, Dec 14, 2011 at 9:56 AM, Joseph Spenner joseph85750@yahoo.com wrote:
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.
Agreed - It has to be fairly common to want to move an existing system to newer hardware - or to restore a backup of a broken system onto a not-quite identical replacement. Anaconda is the only thing that knows how to configure new hardware for booting - and it isn't telling... The only way to get it to help out is to do an install on the target hardware and either keep the resulting /boot partition and /etc/modprobe.conf, overwriting everything else with your backup, or use the info from modprobe.conf to build an initrd containing the right modules before making your backup (assuming the old system still works). The difficulty in handling this operation is a lot of reason for the popularity of virtual machines in spite of the overhead.
On Mon, Dec 12, 2011 at 9:51 AM, Joseph Spenner joseph85750@yahoo.com wrote:
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):
If you do much of this, I'd recommend using the clonezilla-live distro which will automate it and use partclone to avoid having to copy the unused parts of the disk.
(screen shot at http://img214.imageshack.us/img214/645/centosbooterror.jpg%C2%A0%C2%A0 )
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.
I suspect the hardware isn't really identical. Can you boot the source machine from the copied disk?
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Joseph Spenner -
Les Mikesell -
Reindl Harald