Provided by: rdup_1.1.11-1build1_amd64 bug


       rdup-backups - introduction into making backups with rdup


       rdup  is a simple program that prints out a list of files and directories that are changed
       changed on a filesystem. It is 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. These could be used in a pipeline to perform a backup.

       Currently rdup consists out of three basic utilities:

       rdup   With rdup you create the file list on which later  programs  in  the  pipeline  can
              work.  The default output format also includes the files' content. rdup can be seen
              as a tar replacement in this respect,  but  rdup  also  allows  for  all  kinds  of
              transformations  of  the  content  (encryption,  compression, reversal), see the -P
              switch in rdup(1) for more information.

              With rdup-tr you can transform the files rdup delivers to you.  You can create tar,
              cpio  or  pax  files.  You can encrypt pathnames. rdup-tr is filter that reads from
              standard input and writes to standard output.  See rdup-tr(1) for more information.
              With  rdup  and  rdup-tr  you  can  create  an  encrypted archive which is put in a
              directory structure that is also encrypted.

              With rdup-up you can update an existing directory structure  with  the  updates  as
              described by rdup.

              rdup-up  reads rdup input and will create the files, symbolic links, hard links and
              directories (and sockets, pipes and devices) in the file system. See rdup-up(1) for
              more information.

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

           create filelist  |  transform |  update filesystem
           ( rdup           |  rdup-tr   |  rdup-up )

       Note 1:
              The  same sequence is used for restoring. In both cases you want to move files from
              location A to B. The only difference is that the transformation  is  reversed  when
              you restore.

       Note 2:
              The use of rdup-tr is optional.


       For  rdup there is no difference between backups and restores. If you think about this for
       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 during the backup you just need  to  reverse
       those operations during the restore.


       It  is  always  best  to  backup  to another medium, be it a different local harddisk or a
       NFS/CIFS mounted filesystem.  You can also use ssh to store file on a remote  server,  ala
       rsync (although not as network efficient).

       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. Rsync cannot do per-file encryption, sure you can encrypt
       the network traffic with ssh, but at the remote side your files are kept  in  plain  view.
              If  you  implement  remote  backups,  the easy route is to allow root access on the
       backup medium. If the backup runs without root access the  created  files  will  not  have
       their  original  ownership.  For NFS this can be achieved by using no_root_squash, for ssh
       you could enable PermitRootLogin. Note that this may be a security risk.


       We need a little help here in the form of the rdup-simple 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.

              # some tmp files are saved in ~/.rdup. This directory must exist
              DIR=/home     # what to backup
              TODAY=$(date +%Y%m/%d)

              # for remote backup, this has to run on the remote host!

              case $RET in
                   echo Error >&2
                   exit 1
                   # full dump, remove file-list and time-stamp file
                   rm $LIST $STAMP
                   # inc dump
                   # do nothing here
              # this is the place where you want to modify the command line
              # right now, nothing is translated we just use 'cat'
              rdup -N $STAMP -Pcat $LIST $DIR | rdup-up $BACKUP/$HOSTNAME/$TODAY

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


       With  rdup-simple you can easily create backups.  Backing up my home directory to a backup

              rdup-simple ~ /vol/backup/$HOSTNAME

       This will create a backup in /vol/backup/$HOSTNAME/200705/15. So each day  will  have  its
       own directory. Multiple sources are allowed, so:

              rdup-simple ~ /etc/ /var/lib /vol/backup/$HOSTNAME

       Will  backup  your  home  directory, /etc and /var/lib to the backup location. Also if you
       need to compress your backup, simple add a '-z' switch:

              rdup-simple -z ~ /etc/ /var/lib /vol/backup/$HOSTNAME


       For a remote backup to work, both the sending machine and the receiving machine must  have
       rdup installed. The currently implemented protocol is ssh.

       Dumping my homedir to the remote server:

              rdup-simple ~ ssh://miekg@remote/vol/backup/$HOSTNAME

       The  syntax  is  almost  identical,  only  the  destination  starts  with the magic string
       'ssh://'. Compression and encryption are just as easily enabled as with  a  local  backup,
       just add '-z' and/or a '-k keyfile' argument:

              rdup-simple -z -k 'secret-file' ~ ssh://miekg@remote/vol/backup/$HOSTNAME

       Remember  though,  that  because of these advanced features (compression, encryption, etc,
       ...) the network transfer can never be as efficient as rsync.


       rdup(1), rdup-tr(1), rdup-up(1) and