RDUP-BACKUPS(7) 						       rdup							   RDUP-BACKUPS(7)

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 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 per-
       form 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.

       rdup-tr
	      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.

       rdup-up
	      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.

BACKUPS AND RESTORES

       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.

BACKUPS

       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.

SNAPSHOT BACKUPS

       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.

	      #!/bin/bash
	      # some tmp files are saved in ~/.rdup. This directory must exist
	      DIR=/home     # what to backup
	      BACKUP=/vol/backup
	      TODAY=$(date +%Y%m/%d)
	      LIST=~/.rdup/list-$HOSTNAME
	      STAMP=~/.rdup/timestamp-$HOSTNAME

	      # for remote backup, this has to run on the remote host!
	      BUGBUG
	      RET=$?

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

LOCAL BACKUPS

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

	      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

REMOTE BACKUPS

       For a remote backup to work, both the sending machine and the receiving machine must have rdup installed. The currently implemented  proto-
       col 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.

ALSO SEE

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

1.1.x								    15 Dec 2008 						   RDUP-BACKUPS(7)