Backing up on Shutdown

If you have an extra hard drive installed in your system, here's how you can use it to back up important directories and such.

First, keep the hard drive unmounted during normal use, as this entry from /etc/fstab shows:

/dev/sdc1               /backup                  ext3    noauto        1 2

Next, add an extra script to the shutdown process just after killall. For instance, whereas the contents of a stock red hat / fedora core system look like this for /etc/rc.d/rc0.d,

...
lrwxrwxrwx  1 root root 19 Jun 20  2005 K99readahead -> ../init.d/readahead
lrwxrwxrwx  1 root root 25 Jun 20  2005 K99readahead_early -> ../init.d/readahead_early
lrwxrwxrwx  1 root root 17 Jun 20  2005 S00killall -> ../init.d/killall
lrwxrwxrwx  1 root root 14 Jun 20  2005 S01halt -> ../init.d/halt
lrwxrwxrwx  1 root root 17 Jul  6  2004 S18rpcgssd -> ../init.d/rpcgssd
lrwxrwxrwx  1 root root 19 Jul  6  2004 S19rpcidmapd -> ../init.d/rpcidmapd
lrwxrwxrwx  1 root root 20 Jul  6  2004 S19rpcsvcgssd -> ../init.d/rpcsvcgssd

you want to make your backup happen just after the killall and before the halt, like so:

lrwxrwxrwx  1 root root 19 Jun 20  2005 K99readahead -> ../init.d/readahead
lrwxrwxrwx  1 root root 25 Jun 20  2005 K99readahead_early -> ../init.d/readahead_early
lrwxrwxrwx  1 root root 17 Jun 20  2005 S00killall -> ../init.d/killall
lrwxrwxrwx  1 root root 17 Jun 20  2005 S01backup -> ../init.d/backup
lrwxrwxrwx  1 root root 14 Jun 20  2005 S01halt -> ../init.d/halt
lrwxrwxrwx  1 root root 17 Jul  6  2004 S18rpcgssd -> ../init.d/rpcgssd
lrwxrwxrwx  1 root root 19 Jul  6  2004 S19rpcidmapd -> ../init.d/rpcidmapd
lrwxrwxrwx  1 root root 20 Jul  6  2004 S19rpcsvcgssd -> ../init.d/rpcsvcgssd

You could put the symlink in both the /etc/rc.d/rc0.d (shutdown) and /etc/rc.d/rc6.d (reboot) directories, but I just leave it in the shutdown directory because this operation takes a while.

We have not yet seen the shell script named /etc/rc.d/init.d/backup. Here it is:

#!/bin/bash

# added by Manni; backs up certain working directories to /backup drive.

mount /backup

cp -a -v /etc /backup
cp -a -v /root /backup
cp -a -v /home /backup
# anything else in here, like perhaps the directory where
# your postgres database is kept

umount /backup