Difference between revisions of "Cloning a computer"
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| − | Cloning a computer means you have one computer and want to copy | + | Cloning a computer means you have one computer and want to copy the complete harddisk to another. This can mean different things and can have different reasons. |
= Reasons = | = Reasons = | ||
| − | * You want to have a | + | * You want to have a [[backup]] of your computer. In this case it is enough to copy every file from hard disk A to hard disk B. |
* You want to [[virtualize your computer]]. In this case you will have to dump every byte from your source (physical) to your target (virtual) computer. | * You want to [[virtualize your computer]]. In this case you will have to dump every byte from your source (physical) to your target (virtual) computer. | ||
| + | * You are an administrator and want to deploy many computers with the same configuration. | ||
| + | |||
| + | = Ways = | ||
| + | You can either clone byte-by-byte or file-by-file. The advantages are: | ||
| + | * cloning byte-by-byte will clone the boot sector. The system will stay bootable. | ||
| + | * cloning byte-by-byte will even work on a file system the computer does not understand, e.g. an encrypted Windows partition. | ||
| + | * cloning file-by-file will allow you to deploy the system on a smaller partition | ||
| + | * cloning file-by-file will not clone parts of a disk that are not part of a file | ||
| + | |||
| + | = ToConsider = | ||
| + | * Compression keeps your backup small in file size. Plus it accelerates your backup procedure if you have a fast processor and a slow hard disk or network. | ||
| + | * Your /boot/grub/menu.lst will list entries for a boot menu to boot from. The root device can be stated there as /dev/sda, /dev/by-id/whatever, /dev/by-uuid/whatever, /dev/mapper/whatever or some other ways to name the disk. The way that is optimal for cloning is to use the /dev/disk/by-uuid name because this name will be cloned with the disk and be the same even if deployed on another harddisk. | ||
| + | * You may be using more than one partition or harddisk during normal operations. In this case you may want to clone all harddisks/partitions. | ||
= Over the network = | = Over the network = | ||
| + | |||
| + | == file-by-file copy == | ||
| + | To store a backup of one computer on the other via [[network]], use the command: | ||
| + | cd / | ||
| + | tar -cvz $(ls | grep -v proc) | ssh root@<abbr title="replace by your target computer">192.168.178.3</abbr> "cat ><abbr title="replace by the name of your backup file">slash.tar.gz</abbr>" | ||
| + | |||
| + | To clone a computer over the network, say: | ||
cd / | cd / | ||
| − | tar -cv . | ssh root@192.168.0.5 "cat > | + | tar -cv $(ls | grep -v proc) | ssh root@<abbr title="replace by your target computer">192.168.178.3</abbr> "(cd <abbr title="replace by the path where you want to restore, typically /">/public/ubunturoot</abbr>; tar xv )" |
| + | |||
| + | Afterwards you may want to change | ||
| + | * IP address, netmask, gateway, name server, time server, hostname | ||
| + | * /etc/fstab to contain generic device names like /dev/sda1 instead of /dev/disk/by-uuid/7e9e1890-312e-43eb-8ebb-82fe03b62732 | ||
| + | * /boot/grub/menu.lst to contain generic device names | ||
| + | |||
| + | == byte-by-byte copy == | ||
| + | This is how you can clone the harddisk of any computer, even if it is an encrypted Windows computer. | ||
| + | Boot the computer from Knoppix, [[open a console]], enter | ||
| + | [[dd]] if=/dev/sd''x'' | bzip2 -z | ssh root@''192.168.0.5'' "(cat >backup-sd''x''.bz2)" | ||
| + | Be sure to replace /dev/sd''x'' by the harddisk you want to clone and ''192.168.0.5'' by your target computer's IP. | ||
| + | |||
| + | = local = | ||
| + | |||
| + | == file-by-file copy == | ||
| + | Local cloning is e.g. to a USB disk to [[make a USB disk bootable]]. In this case we assume the target disk is ''/dev/sdx2''. To clone your harddisk: | ||
| + | * make sure there is no DVD, CD, network drive and other things mounted | ||
| + | * mount the target harddisk to /mnt: | ||
| + | mount ''/dev/sdx2'' /mnt | ||
| + | * issue the [[command]]s | ||
| + | cd / | ||
| + | tar -cv $(ls | grep -v proc | grep -v sys | grep -v mnt) | ( cd /mnt; tar xv ) | ||
| + | [[mkdir]] /mnt/proc /mnt/sys /mnt/mnt | ||
| + | |||
| + | == byte-by-byte copy == | ||
| + | This is how you can clone the harddisk of any computer locally (e.g. to a USB drive), even if it is an encrypted Windows computer. | ||
| + | * boot the computer from Knoppix | ||
| + | * [[open a console]] | ||
| + | * mount the USB disk, e.g. | ||
| + | mount /dev/sdz1 /mnt/usb | ||
| + | * enter | ||
| + | [[dd]] if=/dev/sd''x'' | bzip2 -z | cat >/mnt/usb/backup-sd''x''.bz2 | ||
| + | Be sure to replace /dev/sd''x'' by the harddisk you want to clone. | ||
| + | |||
| + | = Post cloning steps = | ||
| + | * If you are cloning one harddisk to another byte-by-byte to boot from the other harddisk, make sure the harddisk's ID (/dev/disk/by-id) is not in /boot/grub/menu.lst. Rather, the harddisk's UUID should be there because this will be cloned with the other data. | ||
| + | * change hostname | ||
| + | * change IP address | ||
| + | * under some distributions, e.g. SUSE you have to re-configure [[networking]]. The IP address will be bound to an unknown network device. | ||
| + | * change /etc/hosts so the computer can ping itself | ||
| + | * consider changing the ssh keys ~/.ssh/id_*sa* | ||
| + | |||
| + | = TroubleShooting = | ||
| + | |||
| + | == Your computer does not boot == | ||
| + | If you have cloned a harddisk byte-by-byte and now booting from it does not work, check the device name you are booting from in /boot/grub/menu.lst. The device ID of your harddisk will change, but the UUID will come with the image. So make sure you boot from the device under /dev/disk/by-uuid. | ||
| + | |||
| + | [[Category:Guides]] | ||
Latest revision as of 12:27, 28 March 2015
Cloning a computer means you have one computer and want to copy the complete harddisk to another. This can mean different things and can have different reasons.
Contents
Reasons
- You want to have a backup of your computer. In this case it is enough to copy every file from hard disk A to hard disk B.
- You want to virtualize your computer. In this case you will have to dump every byte from your source (physical) to your target (virtual) computer.
- You are an administrator and want to deploy many computers with the same configuration.
Ways
You can either clone byte-by-byte or file-by-file. The advantages are:
- cloning byte-by-byte will clone the boot sector. The system will stay bootable.
- cloning byte-by-byte will even work on a file system the computer does not understand, e.g. an encrypted Windows partition.
- cloning file-by-file will allow you to deploy the system on a smaller partition
- cloning file-by-file will not clone parts of a disk that are not part of a file
ToConsider
- Compression keeps your backup small in file size. Plus it accelerates your backup procedure if you have a fast processor and a slow hard disk or network.
- Your /boot/grub/menu.lst will list entries for a boot menu to boot from. The root device can be stated there as /dev/sda, /dev/by-id/whatever, /dev/by-uuid/whatever, /dev/mapper/whatever or some other ways to name the disk. The way that is optimal for cloning is to use the /dev/disk/by-uuid name because this name will be cloned with the disk and be the same even if deployed on another harddisk.
- You may be using more than one partition or harddisk during normal operations. In this case you may want to clone all harddisks/partitions.
Over the network
file-by-file copy
To store a backup of one computer on the other via network, use the command:
cd / tar -cvz $(ls | grep -v proc) | ssh root@192.168.178.3 "cat >slash.tar.gz"
To clone a computer over the network, say:
cd / tar -cv $(ls | grep -v proc) | ssh root@192.168.178.3 "(cd /public/ubunturoot; tar xv )"
Afterwards you may want to change
- IP address, netmask, gateway, name server, time server, hostname
- /etc/fstab to contain generic device names like /dev/sda1 instead of /dev/disk/by-uuid/7e9e1890-312e-43eb-8ebb-82fe03b62732
- /boot/grub/menu.lst to contain generic device names
byte-by-byte copy
This is how you can clone the harddisk of any computer, even if it is an encrypted Windows computer. Boot the computer from Knoppix, open a console, enter
dd if=/dev/sdx | bzip2 -z | ssh root@192.168.0.5 "(cat >backup-sdx.bz2)"
Be sure to replace /dev/sdx by the harddisk you want to clone and 192.168.0.5 by your target computer's IP.
local
file-by-file copy
Local cloning is e.g. to a USB disk to make a USB disk bootable. In this case we assume the target disk is /dev/sdx2. To clone your harddisk:
- make sure there is no DVD, CD, network drive and other things mounted
- mount the target harddisk to /mnt:
mount /dev/sdx2 /mnt
- issue the commands
cd / tar -cv $(ls | grep -v proc | grep -v sys | grep -v mnt) | ( cd /mnt; tar xv ) mkdir /mnt/proc /mnt/sys /mnt/mnt
byte-by-byte copy
This is how you can clone the harddisk of any computer locally (e.g. to a USB drive), even if it is an encrypted Windows computer.
- boot the computer from Knoppix
- open a console
- mount the USB disk, e.g.
mount /dev/sdz1 /mnt/usb
- enter
dd if=/dev/sdx | bzip2 -z | cat >/mnt/usb/backup-sdx.bz2
Be sure to replace /dev/sdx by the harddisk you want to clone.
Post cloning steps
- If you are cloning one harddisk to another byte-by-byte to boot from the other harddisk, make sure the harddisk's ID (/dev/disk/by-id) is not in /boot/grub/menu.lst. Rather, the harddisk's UUID should be there because this will be cloned with the other data.
- change hostname
- change IP address
- under some distributions, e.g. SUSE you have to re-configure networking. The IP address will be bound to an unknown network device.
- change /etc/hosts so the computer can ping itself
- consider changing the ssh keys ~/.ssh/id_*sa*
TroubleShooting
Your computer does not boot
If you have cloned a harddisk byte-by-byte and now booting from it does not work, check the device name you are booting from in /boot/grub/menu.lst. The device ID of your harddisk will change, but the UUID will come with the image. So make sure you boot from the device under /dev/disk/by-uuid.
