While BackupPC with it’s web interface is certainly a nice thing to have it imposes a few problems if you want to use it to backup your system. Bare metal restores are more tricky, because files are stored in a proprietary format. Hence you will need to set up BackupPC before you can restore your system, something that is not so trivial.
I looked into another system that would allow me to create a backup of my system completely automated and that would allow for simple bare metal restores. I ended up using tar, as it is a proven tool and is supported even on the most basic live distro you’ll find.
I wrote a small shell script that gives me a few options:
- backup the master boot record
- let exclude certain directories from my backup
- keep defined number of versions of my backup
My entire system backed up like this ends up in a tarball of about 1.8GB.
#check if you are root
if [ $(whoami) != ‚root‘ ]; then
echo „Must be root to run $0″
exit 1;
fi
#base dir to store backup tarball
DIRECTORY=“/path/to/backup“
DATE=`date +%Y%m%d`
#files to exclude
#exclude dynamically created system directories such as /dev or /sys and any other dirs
#you don’t want to include
#also exclude the backup dir
EXCLUDES=(/dev /home /lost+found /media /mnt /proc /sys $DIRECTORY)
#
#
# start of backup
#
#
#copy mbr to file
echo „copying master boot record to /root/mbr.bin…“
dd if=/dev/sda of=/root/mbr.bin bs=512 count=1
len=${#EXCLUDES[*]} #Num elements in EXCLUDES
echo „Backup will exclude the following $len directories:“
i=0
while [ $i -lt $len ]; do
echo „$i: ${EXCLUDES[$i]}“
let i++
done
#prepend –exclude option to every directory
for EXCLUDE in ${EXCLUDES[@]}
do
EXCLUDE=“–exclude=“${EXCLUDE}
EXCLUDELIST=“$EXCLUDELIST $EXCLUDE“
done
#check if backup disk is available
if [ -d „$DIRECTORY“ ]; then
# Will enter here if $DIRECTORY exists
echo „Starting backup with tar cvpzf $DIRECTORY/${DATE}_backup.tgz $EXCLUDELIST /“
#start actual backup process
tar cvpzf $DIRECTORY/${DATE}_backup.tgz $EXCLUDELIST /
echo „change permissions of backup to root only access…“
chmod 700 $DIRECTORY/${DATE}_backup.tgz
echo „${DATE}_backup.tgz has been successfully created.“
echo „Size of backup is `ls -lh $DIRECTORY | grep ${DATE}_backup.tgz | awk ‚{print $5 }’`“
#deleting old versions
BACKUP_VERSIONS=(`ls $DIRECTORY | grep _backup.tgz`)
len=${#BACKUP_VERSIONS[*]}
i=0
#if more than 4 versions exist
if [ $len -gt 4 ]; then
#calculate number of versions to remove
rmno=$(($len-4))
#delete versions at the beginning of the list
while [ $i -lt $rmno ]; do
echo „removing ${BACKUP_VERSIONS[$i]} …“
rm $DIRECTORY/${BACKUP_VERSIONS[$i]}
let i++
done
fi
else
echo „cannot start backup, backup disk is not available“
exit 1
fi
If you want to restore the system you can do so simply by untaring to another disk:
If you are restoring to another disk with a different partition scheme it may be necessary to recreate some entries in /etc/fstab as well as in grub.conf regarding the root device for grub and the kernel.
Restoring the master boot record is equally simple:
bs equals 446 if we do not want to overwrite the partition table that may be different on our new disk. If it’s the same we can also restore with bs=512.
