In this section the shell script will be slightly modified to implement a grandfather-father-son rotation scheme (monthly-weekly-daily):

Here is the new script:

#!/bin/bash #################################### # # Backup to NFS mount script with # grandfather-father-son rotation. # #################################### # What to backup. backup_files="/home /var/spool/mail /etc /root /boot /opt" # Where to backup to. dest="/mnt/backup" # Setup variables for the archive filename. day=$(date +%A) hostname=$(hostname -s) # Find which week of the month 1-4 it is. day_num=$(date +%d) if (( $day_num <= 7 )); then week_file="$hostname-week1.tgz" elif (( $day_num > 7 && $day_num <= 14 )); then week_file="$hostname-week2.tgz" elif (( $day_num > 14 && $day_num <= 21 )); then week_file="$hostname-week3.tgz" elif (( $day_num > 21 && $day_num < 32 )); then week_file="$hostname-week4.tgz" fi # Find if the Month is odd or even. month_num=$(date +%m) month=$(expr $month_num % 2) if [ $month -eq 0 ]; then month_file="$hostname-month2.tgz" else month_file="$hostname-month1.tgz" fi # Create archive filename. if [ $day_num == 1 ]; then archive_file=$month_file elif [ $day != "Saturday" ]; then archive_file="$hostname-$day.tgz" else archive_file=$week_file fi # Print start status message. echo "Backing up $backup_files to $dest/$archive_file" date echo # Backup the files using tar. tar czf $dest/$archive_file $backup_files # Print end status message. echo echo "Backup finished" date # Long listing of files in $dest to check file sizes. ls -lh $dest/

The script can be executed using the same methods as in the section called “Executing the Script”.

It is good practice to take backup media off site in case of a disaster. In the shell script example the backup media is another server providing an NFS share. In all likelihood taking the NFS server to another location would not be practical. Depending upon connection speeds it may be an option to copy the archive file over a WAN link to a server in another location.

Another option is to copy the archive file to an external hard drive which can then be taken off site. Since the price of external hard drives continue to decrease it may be cost affective to use two drives for each archive level. This would allow you to have one external drive attached to the backup server and one in another location.

A tape drive attached to the server can be used instead of a NFS share. Using a tape drive simplifies archive rotation, and taking the media off site as well.

When using a tape drive the filename portions of the script aren't needed because the date is sent directly to the tape device. Some commands to manipulate the tape are needed. This is accomplished using mt, a magnetic tape control utility part of the cpio package.

Here is the shell script modified to use a tape drive:

#!/bin/bash #################################### # # Backup to tape drive script. # #################################### # What to backup. backup_files="/home /var/spool/mail /etc /root /boot /opt" # Where to backup to. dest="/dev/st0" # Print start status message. echo "Backing up $backup_files to $dest" date echo # Make sure the tape is rewound. mt -f $dest rewind # Backup the files using tar. tar czf $dest $backup_files # Rewind and eject the tape. mt -f $dest rewoffl # Print end status message. echo echo "Backup finished" date

Restoring from a tape drive is basically the same as restoring from a file. Simply rewind the tape and use the device path instead of a file path. For example to restore the /etc/hosts file to /tmp/etc/hosts:

mt -f /dev/st0 rewind tar -xzf /dev/st0 -C /tmp etc/hosts