How can completely back up my linux computer so that it can be fully restored easily?

Question

I want to be able to blindly back up my entire hard disk, so that I can blindly and automatically restore in case there is any problem.

I am not interested in merely backing up data, but specifically in how to backup everything, the entire linux operating system with all the configurations, etc.

In other words, If I had second computer with exactly the same hardware, how could I replicate the installation and all the data of the first one without having to install the operating system, configure things and so on?

I have made a full copy using rsync, so that it can be updated. Now, in case something happens again, how can I restore it? I have stored the MBR with dd as well.

Answer 1

There're several ways to accomplish this, if you want an image of your complete installation and have a secondary hard disk (or a network location) as destination, then assuming your installation is on /dev/sda (in this example boot might be /dev/sda1, swap is /dev/sda2, root is /dev/sda3) and your secondary hard disk or network location is mounted at /mnt/backup

dd if=/dev/sda1 | bzip2 -9 > /mnt/backup/boot-image.bz2
dd if=/dev/sda3 | bzip2 -9 > /mnt/backup/root-image.bz2
dd if=/dev/sda count=512 > /mnt/backup/sda.mbr

You'll notice that swap is left out.

To restore the image, you'd boot using a livecd or similar, mount the backup location then run:

# caution this will erase /dev/sda
dd if=/mnt/backup/sda.mbr of=/dev/sda

At this point /dev/sda's partition, table should be restored & visible when you run:

fdisk -l

So you can restore with:

bzcat /mnt/backup/boot-image.bz2 | dd of=/dev/sda1
bzcat /mnt/backup/root-image.bz2 | dd of=/dev/sda3
mkswap /dev/sda2

Remove your bootable media, reboot and your system has been restored

However, it's often not preferable to image large filesystem because garbage in the free space will be included, I'd recommend you skip the steps for sda3 above and instead to backup use:

cd /; tar -cjf /mnt/backup/root.tar.bz2 / -X /tmp/exclude.txt

You would obviously first need to create /tmp/exclude.txt which should list locations to exclude from the backup, for example:

/dev/*
/proc/*
/sys/*
/tmp/*
/mnt/*

Then to restore from your LiveCD or whatever:

mkfs.ext3 -L root /dev/sda3
mkdir /mnt/restore; mount /dev/sda3 /mnt/restore; cd /mnt/restore
tar -xjvpf /mnt/backup/root.tar.bz2 

Or using rsync, in which case just create the filesystem & mount it as above & then rsync the contents back.

Answer 2

Your post is a bit confusing because you ask how to do it, but apparently want to use rsync. Instead, I'd recommend purchasing an external hard drive of adequate size, then cloning the system's disk drive to that hard drive. This is the fastest way I know to recover a complete system.

Answer 3

Since you mention you want to backup the entire disk, the best solution is to use a live CD cloning distribution.

This will allow you to literally copy every sector and partition, either to another drive or to an image file.

The advantage of the cloning approach is that you can compress and encrypt the images, or clone through a network.

You can also choose to restore only specific partitions.

You have not mentioned your operating system, so I will throw ZFS out there (not a product, it is a file system). ZFS allows you to create, transfer and restore snapshots, while the OS is running. You can have multiple snapshots and even versions, with only the changes taking up bandwidth and storage, not the entire disk each time you snapshot it. Again, depending on your operating system, you can have your root partition installed on a ZFS pool.