At Sat, 30 Jul 2011 09:12:28 -0500 CentOS mailing list centos@centos.org wrote:
On 7/30/11 2:03 AM, Benjamin Smith wrote:
On Friday, July 29, 2011 08:02:20 PM Les Mikesell wrote:
If the machines are pretty much identical, clonezilla should work. Boot
the machine with a 'clonezilla-live' CD or USB drive. If you can attach
the target drive to the same machine you can go disk->disk. Otherwise,
connect to something on the network with enough space to hold the image
(ssh, nfs, or a windows share) and clone disk->image, then boot the target
machines and copy image->disk. There is also a server version that will
pxe-boot the targets if you need to do a large number of them.
Thanks for the tip! I'll be trying this out on Monday, but what is the "native" way of doing this?
For disk image copies, you can use 'dd' with the raw disks. But it won't know anything about the filesystem and will copy all sectors. Clonezilla will use partclone (or ntfsclone for windows) and only copy the used blocks so it is much faster with large disks. In any case the partitions must be unmounted or at least not changed while being copied, so you need to boot from something else.
dump/restore is a 'native' file system copy method. Doing this in single-user mode works extremely well, although the really paranoid can always boot up either a live cd or the boot/install cd in rescue mode. I've done this countless times in either single-user mode and sometimes in full multi-user mode (on a 'quiet' system). (dump can dump *unmounted* file systems.)
dd can be problematical if the target and source disks are different (sizes, geometry, etc.), since dd will do a literal sector-by-sector copy, which is not generally advisable (and why o why to people *keep* suggesting it? -- it is really a misuse of dd, unless you *really* know what you are doing).
I recommend the ubuntu-based version of clonezilla for better hardware support. Also, you'll need to fix up the network settings and hostname on each clone after you bring it up.