Source: backup.sh.txt

#!/opt/bin/bash

# Written for Solaris.  Should be simple to port to other systems.
# Change the tape device, the remote program (rsh or ssh), and
# choose your dump program.  This script assumes you know what you're doing
# with .rhosts, hosts.equiv and/or ssh keys so that you will not need to
# input passwords to do this.  This script is designed to run from cron,
# but I see nothing wrong with running it manually.
#
# This script will by default append to existing information on a tape.
# If you would like to nuke the tape, you can simply call this script with
# the --scratch parameter.
#
# Note that this script makes *NO* provisions for restoring your data.
# If your box dies, you'll need to attach a tape drive to your server's
# SCSI chain and run a restore locally, after booting from a CD, floppy,
# Jaz disk, or something else.  Jaz drives make really cool emergency 
# startup systems for times like this.  You can have the convenience of a 
# fully functioning system on a 3.5" disk.  If you can boot the machine,
# AND have network connectivity, you can restore over the network, using
# a technique similar to this script....
# 
# Make sure the tape device you choose is a non-rewinding device!


tape=/dev/rmt/0cn
remote=rsh
dump=ufsdump

# dumpit remote filesystems and writes the output to a local tape
dumpit() {
  host=$1
  fsys=$2
  fno=`expr $fno + 1`
  echo ======================================================================
  echo File $fno on $tape
  echo Host: $host
  echo Filesystem: $fsys
  echo Started `date`
  echo "$remote -n $host \"cd $fsys && $dump 0f - .\" | dd of=$tape bs=256k"
  $remote -n $host "cd $fsys && $dump 0f - ." | dd of=$tape bs=256k
  if [ $? != 0 ]; then
    echo Error writing tape $tape
    echo No more backups for now
    exit 1
  fi
  echo Finished `date`
  echo
  echo
};

if [ "$1" = "--help" ]; then
  cat <<EOF;

Your only option is the --scratch parameter.  If you use it, all data on
your tape will be destroyed.

For options regarding what tape device to use, and so forth, set them at
the top of the script.
EOF
  exit 0
fi

if [ "$1" = "--scratch" ]; then
  echo Writing from the beginning of the tape $tape
  mt -f $tape rewind
  mt -f $tape eof
else
  # does not overwrite whatever is written already
  mt -f $tape eom > /dev/null 2>&1
fi

# This works on Solaris.  Other mt's may not behave the same way.  YMMV.
fno=`mt -f $tape stat | grep 'file no' | \
      sed 's/.*file no= \([0-9][0-9]*\).*/\1/'`

if [ "$fno" = "" ]; then
  echo No tape in the device $tape
  echo Abort backup
  exit 1
fi

echo Starting backup at `date`
echo Current position of $tape is $fno

# several filesystems on one box.
dumpit box1 /
dumpit box1 /usr
dumpit box1 /var
dumpit box1 /home

# several filesystems on many boxen.
for host in box2 box3 box4; do
  dumpit $host /
  dumpit $host /var
  dumpit $host /home
done

echo ""
echo "All Backups complete!"
mt -f $tape rewind