Hey. I've done this in the past, the very far past, and now I find myself back in the Linux world after many years. I need help with remember all the steps for cloning and then booting from a clone.

I have:

/dev/sda1 boot
/dev/sda2 / (root)
/dev/sda3 /home

I want to clone and boot from and have other data on:
/dev/sdc1 boot
/dev/sdc2 / (root)
/dev/sdc3 /home

I know I will need to point grub to /dev/sdc and probably fix fstab. If have completed the fdisk setup of /dev/sdc. Seems I remember sfdisk being used, as well as dd. Any input would be greatly appreciated.

This is a CentOS 5.8 installation.

There may be a Centos way to clone so you should read their (RH/IBM) documentation.

I guess one could use any number of file based copy means. Each one tends to need a live boot usually. There is at least one live state linux backup but I've never used it.
Things like rsync, tar, cpio partimage and gparted as well as others could copy usually.

dd is a tool that can be used to clone off a number of parts of a drive or entire drive. It's not an elegant way and has some issues.


As in most cases you have to fix all naming from grub to disk mounting to network naming either before clone or after.

Also look at dump/restore (or xfsdump/xfsrestore depending on filesystem type).
I have used this and it works! Yes, you will have to update fstab.

If you are going to keep sda installed in the server then update menu.lst otherwise you will have to install GRUB bootloader to the MBR (on sdc disk).

sounds about right; you need to point it to the correct partitions. i recommend using UUIDs.
any plain text editor will do for that.

why such an old, outdated version of centos?

Thanks all for you responses. I appreciate it. The purpose of the clone was to do an update on the clone and preserve the original boot disk. I was told that by a vendor that he had used yum update to take an older version of Linux, like 5, straight to 7. I have serious doubts that this kind of update would actually work ... but I wanted to try it. There are a lot of warnings online about doing such and it is not supported anywhere that I can find. The goal though is to update the older version of CentOS either by updating the clone or a new/clean install.

Gotta wonder which vendor told you that...

Having just done it, I can verify the only way to get from 5.8 to 7.x is with a clean install. Afterwards, you can copy the data (/home) over and use your backup of the various config files to update the new config files...NOT recommending you copy them over, however. There are some significant changes in the apache configuration, for example.

Also, 5.x is SystemV init; 7.x is SystemD -- major change!