Practicality of backing up huge hard drives (was Re: [mythtv-users] Dieing Hard Drive)

[Matthew Schumacher]

Matthew Schumacher wrote:
> I haven't followed this thread, but thought I would post my backup 
> script in case it is useful to someone.
> 
> It uses rsync to rotate the backup, and it keeps the disk space down 
> because files that remain the same though the rotations are hard links 
> to the same physical space on the disk.  This allows you to have a 7 day 
> rotation, while the disk space used is kept to the sum of the data and 
> the change over the last 7 days.
> 
> schu
> 

The list stripped my code, how annoying...

WATCH FOR LINE WRAP!!!

#!/bin/bash

#
# Schu's backup rotation script modified from 
http://www.mikerubel.org/computers/rsync_snapshots/
#
# Dirs in the includes file are appended to the backupsource and backed 
up. So if /etc/rotateBackup.includes
# contains 'var' on a line and the backup source is '/' then /var will 
be backed up.
#

# user changable stuff
BACKUPSOURCE=/
BACKUPDEST=/backup
EXCLUDES=/etc/rotateBackup.excludes
INCLUDES=/etc/rotateBackup.includes

# make sure we're running as root
if (( `id -u` != 0 )); then { echo "Sorry, must be root.  Exiting..."; 
exit; } fi

# if the excludes file does exist then touch it
if [ ! -f $EXCLUDES ]; then
   touch $EXCLUDES
fi

# if the includes file does exist then touch it
if [ ! -f $INCLUDES ]; then
   touch $INCLUDES
fi

# now rotate snapshots

# step 1: delete the oldest snapshot, if it exists:
if [ -d $BACKUPDEST/backup.6 ]; then
   rm -rf $BACKUPDEST/backup.6
fi

# step 2: shift the middle snapshots(s) back by one, if they exist
if [ -d $BACKUPDEST/backup.5 ]; then
   mv $BACKUPDEST/backup.5 $BACKUPDEST/backup.6
fi;

if [ -d $BACKUPDEST/backup.4 ]; then
   mv $BACKUPDEST/backup.4 $BACKUPDEST/backup.5
fi;

if [ -d $BACKUPDEST/backup.3 ]; then
   mv $BACKUPDEST/backup.3 $BACKUPDEST/backup.4
fi;

if [ -d $BACKUPDEST/backup.2 ]; then
   mv $BACKUPDEST/backup.2 $BACKUPDEST/backup.3
fi;

if [ -d $BACKUPDEST/backup.1 ]; then
   mv $BACKUPDEST/backup.1 $BACKUPDEST/backup.2
fi

# step 3: make a hard-link-only (except for dirs) copy of the latest 
snapshot,
# if that exists
if [ -d $BACKUPDEST/backup.0 ]; then
   cp -al $BACKUPDEST/backup.0 $BACKUPDEST/backup.1
fi;

# step 4: rsync from the system into the latest snapshot (notice that
# rsync behaves like cp --remove-destination by default, so the destination
# is unlinked first.  If it were not so, this would copy over the other
# snapshot(s) too!
rsync -va -r --delete --delete-excluded --files-from="$INCLUDES" 
--exclude-from="$EXCLUDES" $BACKUPSOURCE/ $BACKUPDEST/backup.0

# step 5: update the mtime of hourly.0 to reflect the snapshot time
touch $BACKUPDEST/backup.0