[oclug] good backup script or not
bartom at nwsca.com
Fri Mar 16 19:48:24 EST 2001
I am looking for a way to copy my Linux hard drive to a 2nd hard drive to
back it up. I found the script shown below and I like it because it is
configurable for files to back up. I found it at
http://www.xs4all.nl/~voorburg/backup.html . My concern here is that it
might not be copying hidden files, if they exist on a Linux OS and once I
have the drive copied is there anything else I would have to do to make it
usable. Is there a simpler way to do this copy, for example could I just ftp
everything from one drive to the other once a day?
Backup script for Linux using tar and find
Every Linux distribution provides a range of utilities that you can use to
make backups of your files. Here is the how I get the job done with crontab
and a shell script using tar and find
I wanted to secure all the data-files on my system on a regular basis.
Regular for me implies on an automated basis. I've tried doing a manual
backup every week or so but that caused too much hassle, so effectively I
stopped making backups....
Further, I wanted to have an up-to-date backup of the most essential
configuration settings on my system. This would help me in case I
accidentally lost some datafiles or setting on my system. In case of losing
everything I would need to reinstall my Linux distribution (plus extra
installed software) and restore data files and settings. I decided that a
full backup of the whole system wouldn't be worth the effort (and
Choice of hardware
Say "backup" and most Unix people think "tapedrive". However, nowadays
harddrives come that cheap that I chose to add an extra harddrive to my AMD
400 machine. This cheap option has the advantage that a harddrive can be
mounted automatically, no need for manually inserting tapes. A disadvantage
is that the backup resides in the same physical unit as the very data it is
supposed to secure. However, since I do have a CD-writer om my local network
I still have the option to copy a backup to a CD once in a while.
My main HD is 6Mb. The backup HD has 10Mb.
After adding the drive to my machine I wrote a little shell script (for
bash) that basically does the following:
it mounts my backupdrive
it checks the date
every sunday it makes a full backup of some datafiles and some configuration
settings, older incremental backups are removed. other days it backups files
that have been accessed the last day
it dumps all the contents of a mysql database to the backup drive and zips
it unmounts the backup drive
This script (I've stored it in /root/scripts) is called every night at 3:01
AM by cron. The crontab file looks like:
1 3 * * * /root/scripts/daily_backup
Add this line using contab -e when root.
Here's the actual code:
# creates backups of essential files
# rv: oct. 6, 2000 : changed "find -atime +1" to "find -ctime +1"
# rv: oct. 8, 2000 : fixed incorrect use of find for incremenal backups
# find -ctime -1 iso find -ctime +1
# (thanks to Gysbert Rochat)
DATA="/home /root /usr/local/httpd"
CONFIG="/etc /var/lib /var/named"
if test "$1" = "Sun" ; then
# weekly a full backup of all data and config. settings:
tar cfz "/mnt/backup/data/data_full_$6-$2-$3.tgz" $DATA
rm -f /mnt/backup/data/data_diff*
tar cfz "/mnt/backup/config/config_full_$6-$2-$3.tgz" $CONFIG
rm -f /mnt/backup/config/config_diff*
# incremental backup:
find $DATA -depth -type f -ctime -1 -print > $LIST
tar cfzT "/mnt/backup/data/data_diff_$6-$2-$3.tgz" "$LIST"
rm -f "$LIST"
find $CONFIG -depth -type f -ctime -1 -print > $LIST
tar cfzT "/mnt/backup/config/config_diff_$6-$2-$3.tgz" "$LIST"
rm -f "$LIST"
# create sql dump of databases:
mysqldump -u root --password=mypass --opt mydb >
All my data files are in /root, /home or /usr/local/httpd.
I chose to backup all the setting in /etc (where most essential settings are
stored), /var/named (nameserver settings) and /var/lib (not sure about the
importance of this one...). I might need to add more to the list but I still
far from being a Unix-guru ;-). All suggestions are welcome!
tar versus cpio
The first version of this script used cpio to create backups iso tar.
However, I found the cpio format not very handy for restoring single files
so I chang ed it to tar. A disadvantage of using tar is that you can't (as
far as I know) simply pipe the output of a find to it.
Using a construct like tar cvfz archive.tgz `find
/home -ctime -1 -depth -print` caused errors for files that contained a
space " " character. This problem was solved by wring the output of find to
a file first (and using tar with the -T option).
voorburg at xs4all.nl
More information about the OCLUG