Provided by: rdup_0.7.0-1_i386 bug

NAME

       rdup-backups - introduction into making backups with rdup

INTRODUCTION

       rdup  is  a  simple  program  that  prints  out  a  list  of  files and
       directories that are changed changed on a filesystem. It is  much  more
       sophisticated than for instance find, because rdup will find files that
       are removed or directories that are renamed.

       A long time ago rdup included a bunch of shell and  Perl  scripts  that
       implemented  a  backup  policy.   Currently  rdup consists out of three
       basic utilities:

       rdup   With rdup you create the filelist on which later programs in the
              pipeline  can  work.  With  rdup  -c the file’s contents is also
              echo-ed to stdout.

       rdup-tr
              With rdup-tr you can transform (encrypt, compress,  whatever...)
              the files rdup delivers to you.

              rdup-tr reads rdup input and will create rdup -c output.

       rdup-up
              With rdup-up you can update an existing directory structure with
              the updates as describe in the rdup archive.

              rdup-up reads rdup -c input and will create the files, symlinks,
              hardlinks  and directories (and sockets, pipe and devices on the
              file system.

       So the general backup pipeline for rdup will look some like this:

           create filelist  |  transform file content  |  update filesystem

       There is also a little shell script that can be used to create  a  hard
       linked  directory  structure,  this  script  rdup-ln.sh is installed in
       ’/usr/lib/rdup/’. The script looks back for previous  backup  and  then
       creates  a  hardlinked  directory  structure.  By using this script you
       create a YYYYMM/DD backup structure,  where  each  YYYYMM/DD  directory
       contains  a full view of your filesystem at that date. This script very
       much depends on being able to use GNU date and GNU cp.

       From the return code of this script you know what to do,  if  the  exit
       code is 0 an incremental backup needs to be made. If the exit code is 1
       a full backup is in order. An exit code of 2 means there was some  kind
       of error.

       With  these three (four) tools you can create your own backup solution,
       see SNAPSHOT BACKUPS later in this document.

TYPES OF OUTPUT

       rdup can create two types of output:

       1.     a list of pathnames and path attributes

       2.     a list of pathnames and path attributes and the files’ contents

       The latter is often called ’rdup -c’ output after the switch (-c) which
       enables  this  ouput. ’rdup -c’ output is comparable to archive formats
       like tar or pax.

       The first one is just called the normal or list output.

       In rdup(1), rdup-tr(1) and rdup-up(1) it says what output a command can
       create and what input it expects.

BACKUPS AND RESTORES

       For  rdup  there  is no difference between backups and restores. If you
       think about this a minute you understand why.

       Making a backup means copying a list of files somewhere else. Restoring
       files is copying a list of files back to the place they came from. Same
       difference. So rdup can be used for both, if you did any transformation
       with  rdup-tr  during  the  backup  you  just  need  to  reverse  those
       operations during the restore.

BACKUPS

       It is always best to backup to another medium, be it a different  local
       harddisk  or  a  NFS/CIFS  mounted  filesystem or use the remote backup
       capabilities (-c) to securely copy the backup  to  another  system  all
       together.

       If  you  backup to a local disk you can just as well use rsync or plain
       old tar, but if you store your files at somebody else’s disk  you  will
       need  encryption.  This is where you go beyond rsync and rdup comes in.

SNAPSHOT BACKUPS

       We need a little help here in the form of the rdup-ln.sh script.   Keep
       in  mind  that  the following scripts can also be run remotely with the
       help of ssh.

       The following script implements the algorithm of rdup-simple.

              #!/bin/bash

              # some tmp. file are saved in ~/.rdup. This directory must exist

              DIR=/home     # what to backup
              BACKUP=/vol/backup
              TODAY=$(date +%Y%m/%d)   # same as in rdup-ln.sh
              LIST=~/.rdup/list-$HOSTNAME
              STAMP=~/.rdup/timestamp-$HOSTNAME

              # for remote backup, this has to run on the remote host!
              /usr/lib/rdup/rdup-ln.sh $BACKUP/$HOSTNAME
              RET=$?

              case $RET in
                  2|*)
                   echo Error >&2
                   exit 1
                   ;;
                  1)
                   # full dump, remove filelist and timestamp file
                   rm $LIST $STAMP
                   ;;
                  0)
                   # inc dump
                   # do nothing here
                   ;;
              esac

              # this is the place where want to modify the commandline
              # right now, nothing is translated we just use ’cat’

              rdup -N $STAMP $LIST $DIR | rdup-tr -Pcat | rdup-up $BACKUP/$HOSTNAME/$TODAY

              # or do a remote backup
              #rdup -N $STAMP $LIST $DIR | rdup-tr -Pcat | ssh root@remotehost \
              #    rdup-up $BACKUP/$HOSTNAME/$TODAY

ALSO SEE

       rdup(1), rdup-tr(1), rdup-up(1) or http://www.miek.nl/projects/rdup/