There
are various strategies for a backup depending on the method that
suits your needs. Lastly the “best backup policy” will be the one
that is tested and works as per your needs.
METHOD-1
(Manual)
Here
we will see how to backup the data, and applications installed from
the repositories of Ubuntu.
Step-1
Backup of List of All Applications
Assume
if for some reason your system is not able to boot and you dont have
any choice other than reinstalling the operating system. There is
least possibility for anyone to remember the whole lot of packages
and applications that are installed on the system. In that case there
is a quick way to store a list of all installed applications and
packages in a text file. This text file can be used to install all
your packages automatically. This method will help you save an
incrdible amount of time, especially when you need to repeat the same
task multiple number of times.
So,
first you have to retrieve all your installed packages to a list. You
can do so by redirecting the output to a file, example –
applist.txt. You need to save this file to some place so that you can
use it in future for the restore process.
Follow
the below mentioned steps to proceed further.
Creating
backup
1.
Open the terminal and execute the below command to backup the list
of your installed applications.
$
sudo dpkg –get-selections > applist.bkp
Now
you can move the applist.txt file to some safe location (CD, DVD,
Pendrive, etc.)
Restoring
backup
You can restore
your packages after a new/fresh installation of Ubuntu by moving into
the folder containing your text file and follow the below mentioned
steps.
$
sudo apt-get install aptitude
$
sudo dpkg –clear-selections
$
sudo dpkg –set-selections <applist.bkp>
$
sudo aptitude install
Then
follow given prompts.
APTonCD,
and easy GUI tool serves the same purpose.
Step-2 Backup
your Data.
Most of us
normally keep our data in /home. Other customizations and settings
would also reside in /home. If there is some place other than /home
where you keep your data, that should also be included respectively.
Step-3 Backup
the System Settings.
It
is a good practice to keep a copy of all system critical files like
/etc/fstab, /etc/passwd, /etc/shadow, /etc/group, /etc/sudoers,
/etc/hostname, and /etc/hosts. As you can see all these files are
very important and are all contained in /etc, so it is more
convenient to backup all of /etc directory.
Step-4 Backup
Partition Table
Partition table
backup proves useful in case where we need to replace a damaged hard
disk and to replace the old partition table onto the new disk.
To create a copy
of partition table using the below mentioned command.
$ sudo fdisk -l
> fdisk.bkp
or
$ sudo sfdisk -d
/dev/xyz > /<path_to_file>/sfdisk.bkp
To restore the
partition table follow the below mentioned steps
$ sudo sfdisk
/dev/xyz < /<path_to_file>/sfdisk.bkp
Step-5 Backup
your MBR
MBR
is located in the first sector of hard disk and is commonly known for
finding the bootable partitions in the partition table. It loads the
boot sector i.e. boot loader. A damaged or corrupted MBR means that
the operating system will fail to load. MBR resides in 512 byte boot
sector, where 446 bytes is reserverd for bootstrap, 64 bytes for
partition table and 2 bytes for signature.
MBR Backup
$
sudo dd if=/dev/xyz of=/<path_to_file>/mbr.bkp bs=512 count=1
Use
“bs=446” to copy just the MBR.
Destroy MBR
To
clear the MBR including the partition table use the below command. In
case if you can to just kill the MBR and keep the partition table
intact then simply change the value 512 to 446.
$
sudo dd if=/dev/zero of=/dev/xyz bs=512 count=1
MBR Restore
You
can copy the MBR backup file to some pendrive and boot the machine
using a live-CD and execute the below command to restore the old MBR.
$
sudo dd if=/<path_to_file>/mbr.bkp of=/dev/xyz bs=512 count=1
Replace
xxx with the actual device name such as /dev/sda or /dev/hda. Actual
device name can be found using the below command.
$
sudo sfdisk -l
Reinstallation of
GRUB using the install CD in rescue mode will also give the same
effect, without touching the partition table. There are many other
ways to restore the MBR. There are many tools and live-CDs available
to do so such as UbuntuSecureRemix,
Boot-Repair-CD
and TestDisk.
You can google out many different ways and implement as per your
convenience.
Step-6 Final
backup
Finally you can
also backup some additional directories like /usr/local, /opt or
/usr/share, it may be anything that you have customized and put
everything into an archive.
Create an
archive
$ sudo tar
-cvzfp backup.tar.gz /home /root /etc /<path_to_file>/mbr.bkp
/<path_to_file>/sfdisk.bkp /<path_to_file>/applist.bkp
Restore
archive
$ sudo tar xvzfp
backup.tar.gz -C /
METHOD-2
(Using images)
Backing up data
using images is very easy with the help of some tools like Partimage
and Clonezilla. Even command
line tools like dd, tar and rsync have proved very efficient in
backups containing large data. The only disadvantage of image backups
is its large size. Since it is very simple to just copy and compress
the data to an image, it does backup everything on the partition.
Normally everyone needs small backup containing only the data and
settings on their machine, because of which this method is rarely
used.
Note:
Always test your backup before you implement it.
Any
suggestions are more than welcome.
