Rsync

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Installing and using the ipkg application Rsync

Introduction

Rsync is a great tool for synchronising files from disk to disk, or across a network connection. Some smart coding means that if you have two almost similar files then only the changes are copied over.

Rsync uses the "rsync algorithm" which provides a very fast method for bringing remote files into sync. It does this by sending just the differences in the files across the link, without requiring that both sets of files are present at one of the ends of the link beforehand.

Some features of rsync include

  • can update whole directory trees and filesystems
  • optionally preserves symbolic links, hard links, file ownership, permissions, devices and times
  • internal pipelining reduces latency for multiple files
  • can use rsh, ssh or direct sockets as the transport


Installation

  1. Install ipkg
  2. Make sure you have an internet connection
  3. Log on and su to root
/ # ipkg install rsync
Installing rsync (2.6.8-1) to root...
Downloading http://ipkg.nslu2-linux.org/feeds/optware/ds101/cross/stable/rsync_2.6.8-1_armeb.ipk
Configuring rsync
/opt/etc/init.d/S57rsyncd: 5: pidof: not found
Successfully terminated.

The pidof error is since FSG does not include the utility pidof. The rsync daemon will also not run after the first reboot since the startup file appears to be the shutdown script which is installed at /opt/etc/init.d/S57rsyncd which therefore won't be touched (since it should be in /etc/rc/). This isn't really a problem though since you shouldn't need the daemon for anything since it's safer to tunnel it over SSH instead.

(The pidof tool is contained in the package busybox-links)

Usage

To copy from disk to disk

Simply enter:

rsync -auv ''source'' ''destination''

e.g.

rsync -auv /home/LaCie_Hard_Drive_USB/Music/* /home/Music/

This will copy the entire directory tree from source to destination, synchronising it if some (or all) of it is already there.

To copy across the network

Both sides must have ssh and rsync - for a PC running windows you probably want to look at Cygwin and install and set up an ssh server.

If you want to log in without passwords using a pre-shared secret key then look at this advanced tutorial, however remember this is a backdoor that someone else might use to get your data!

You use rsync the same way except you tell it to use ssh as transport.

rsync -auvz --rsh=ssh ''source'' ''destination''

Either (or both) of the source and destination are in SSH syntax like:

user@host:/directory
or
user@host:/directory/file

e.g.

rsync -auvz --rsh=ssh Administrator@windowsPC:/cygdrive/c/music/* /home/Music/

Options

Very useful ones are:

  • The v option will produce logging of every file moved
  • The --progress will do a percentage bar for each file copied
  • The z option will compress the data before sending it - most useful on a network.


If you type rsync you will get the help page

rsync  version 2.6.8  protocol version 29
Copyright (C) 1996-2006 by Andrew Tridgell, Wayne Davison, and others.
<http://rsync.samba.org/>
Capabilities: 64-bit files, no socketpairs, hard links, symlinks, batchfiles,
              inplace, IPv6, 64-bit system inums, 64-bit internal inums
 
rsync comes with ABSOLUTELY NO WARRANTY.  This is free software, and you
are welcome to redistribute it under certain conditions.  See the GNU
General Public Licence for details.
 
rsync is a file transfer program capable of efficient remote update
via a fast differencing algorithm.
 
Usage: rsync [OPTION]... SRC [SRC]... DEST
  or   rsync [OPTION]... SRC [SRC]... [USER@]HOST:DEST
  or   rsync [OPTION]... SRC [SRC]... [USER@]HOST::DEST
  or   rsync [OPTION]... SRC [SRC]... rsync://[USER@]HOST[:PORT]/DEST
  or   rsync [OPTION]... [USER@]HOST:SRC [DEST]
  or   rsync [OPTION]... [USER@]HOST::SRC [DEST]
  or   rsync [OPTION]... rsync://[USER@]HOST[:PORT]/SRC [DEST]
The ':' usages connect via remote shell, while '::' & 'rsync://' usages connect
to an rsync daemon, and require SRC or DEST to start with a module name.
 
Options
 -v, --verbose               increase verbosity
 -q, --quiet                 suppress non-error messages
 -c, --checksum              skip based on checksum, not mod-time & size
 -a, --archive               archive mode; same as -rlptgoD (no -H)
     --no-OPTION             turn off an implied OPTION (e.g. --no-D)
 -r, --recursive             recurse into directories
 -R, --relative              use relative path names
     --no-implied-dirs       don't send implied dirs with --relative
 -b, --backup                make backups (see --suffix & --backup-dir)
     --backup-dir=DIR        make backups into hierarchy based in DIR
     --suffix=SUFFIX         set backup suffix (default ~ w/o --backup-dir)
 -u, --update                skip files that are newer on the receiver
     --inplace               update destination files in-place (SEE MAN PAGE)
     --append                append data onto shorter files
 -d, --dirs                  transfer directories without recursing
 -l, --links                 copy symlinks as symlinks
 -L, --copy-links            transform symlink into referent file/dir
     --copy-unsafe-links     only "unsafe" symlinks are transformed
     --safe-links            ignore symlinks that point outside the source tree
 -k, --copy-dirlinks         transform symlink to a dir into referent dir
 -K, --keep-dirlinks         treat symlinked dir on receiver as dir
 -H, --hard-links            preserve hard links
 -p, --perms                 preserve permissions
 -E, --executability         preserve the file's executability
     --chmod=CHMOD           change destination permissions
 -o, --owner                 preserve owner (super-user only)
 -g, --group                 preserve group
     --devices               preserve device files (super-user only)
     --specials              preserve special files
 -D                          same as --devices --specials
 -t, --times                 preserve times
 -O, --omit-dir-times        omit directories when preserving times
     --super                 receiver attempts super-user activities
 -S, --sparse                handle sparse files efficiently
 -n, --dry-run               show what would have been transferred
 -W, --whole-file            copy files whole (without rsync algorithm)
 -x, --one-file-system       don't cross filesystem boundaries
 -B, --block-size=SIZE       force a fixed checksum block-size
 -e, --rsh=COMMAND           specify the remote shell to use
     --rsync-path=PROGRAM    specify the rsync to run on the remote machine
     --existing              ignore non-existing files on receiving side
     --ignore-existing       ignore files that already exist on receiving side
     --remove-sent-files     sent files/symlinks are removed from sending side
     --del                   an alias for --delete-during
     --delete                delete files that don't exist on the sending side
     --delete-before         receiver deletes before transfer (default)
     --delete-during         receiver deletes during transfer, not before
     --delete-after          receiver deletes after transfer, not before
     --delete-excluded       also delete excluded files on the receiving side
     --ignore-errors         delete even if there are I/O errors
     --force                 force deletion of directories even if not empty
     --max-delete=NUM        don't delete more than NUM files
     --max-size=SIZE         don't transfer any file larger than SIZE
     --min-size=SIZE         don't transfer any file smaller than SIZE
     --partial               keep partially transferred files
     --partial-dir=DIR       put a partially transferred file into DIR
     --delay-updates         put all updated files into place at transfer's end
 -m, --prune-empty-dirs      prune empty directory chains from the file-list
     --numeric-ids           don't map uid/gid values by user/group name
     --timeout=TIME          set I/O timeout in seconds
 -I, --ignore-times          don't skip files that match in size and mod-time
     --size-only             skip files that match in size
     --modify-window=NUM     compare mod-times with reduced accuracy
 -T, --temp-dir=DIR          create temporary files in directory DIR
 -y, --fuzzy                 find similar file for basis if no dest file
     --compare-dest=DIR      also compare destination files relative to DIR
     --copy-dest=DIR         ... and include copies of unchanged files
     --link-dest=DIR         hardlink to files in DIR when unchanged
 -z, --compress              compress file data during the transfer
     --compress-level=NUM    explicitly set compression level
 -C, --cvs-exclude           auto-ignore files the same way CVS does
 -f, --filter=RULE           add a file-filtering RULE
 -F                          same as --filter='dir-merge /.rsync-filter'
                             repeated: --filter='- .rsync-filter'
     --exclude=PATTERN       exclude files matching PATTERN
     --exclude-from=FILE     read exclude patterns from FILE
     --include=PATTERN       don't exclude files matching PATTERN
     --include-from=FILE     read include patterns from FILE
     --files-from=FILE       read list of source-file names from FILE
 -0, --from0                 all *-from/filter files are delimited by 0s
     --address=ADDRESS       bind address for outgoing socket to daemon
     --port=PORT             specify double-colon alternate port number
     --sockopts=OPTIONS      specify custom TCP options
     --blocking-io           use blocking I/O for the remote shell
     --stats                 give some file-transfer stats
 -8, --8-bit-output          leave high-bit chars unescaped in output
 -h, --human-readable        output numbers in a human-readable format
     --progress              show progress during transfer
 -P                          same as --partial --progress
 -i, --itemize-changes       output a change-summary for all updates
     --log-format=FORMAT     output filenames using the specified format
     --password-file=FILE    read password from FILE
     --list-only             list the files instead of copying them
     --bwlimit=KBPS          limit I/O bandwidth; KBytes per second
     --write-batch=FILE      write a batched update to FILE
     --only-write-batch=FILE like --write-batch but w/o updating destination
     --read-batch=FILE       read a batched update from FILE
     --protocol=NUM          force an older protocol version to be used
 -4, --ipv4                  prefer IPv4
 -6, --ipv6                  prefer IPv6
     --version               print version number
(-h) --help                  show this help (-h works with no other options)
 
Use "rsync --daemon --help" to see the daemon-mode command-line options.
Please see the rsync(1) and rsyncd.conf(5) man pages for full documentation.
See http://rsync.samba.org/ for updates, bug reports, and answers
rsync error: syntax or usage error (code 1) at main.c(1216) [client=2.6.8]

How to use it to backup from windows with Cygwin to your FSG

  • Install Cygwin on your Windows PC.
mkdir -p /home/External_blah/backup-dir
ln -s /home/External_blah/backup-dir /home/backup

Replace External_blah with the name your FSG has for your external drive and replace backup-dir with what you want the backup directory to be called on the external drive.

  • Create two files

File: backup.cmd on your desktop (or where you want it to run - startup or shutdown folders are also useful)

@echo off
c:\cygwin\bin\bash --login -i -c "backup.sh"

File: backup.sh in c:\cygwin\bin\

$ rsync -auzv --rsh=ssh /cygdrive/c/Documents\ and\ Settings/Matt/My\ Documents/My\ Pictures/  'admin@192.168.1.2:/home/backup/Matt/Freya/My\ Documents/My\ Pictures'

Replace the windows username ("Matt") and the computer name ("Freya") with your own.

Note: Cygwin is very picky about those quotes and backslashes - test them out first on the cygwin command line with a :

ls /cygdrive/c/Documents\ and\ Settings/Matt/My\ Documents/My\ Pictures/
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