Rsync

Posted under » Ubuntu » Linux on 30 November 2010

Rsync is a fast and extraordinarily versatile file copying tool. It can copy locally, to/from another host over any remote shell, or to/from a remote rsync daemon. It offers a large number of options that control every aspect of its behavior and permit very flexible specification of the set of files to be copied. It is famous for its delta-transfer algorithm, which reduces the amount of data sent over the network by sending only the differences between the source files and the existing files in the destination. Rsync is installed in ubuntu by default.

The simplest method for backing up over a network is to use rsync via SSH (using the -e ssh option). Alternatively, you can use the rsync daemon (see Rsync Daemon which requires much more configuration. Local backup only requires rsync and read/write access to the folders being synchronized.

A network sync can be performed locally so long as the folder is shared (say by Samba) and then mounted to the machine with folder1. This process gets around having to use ssh but is less secure and should only be used in secure private networks, like at your home.

Local Backup

rsync -azvv /home/path/folder1/ /home/path/folder2

Backup Over Network can be done via ssh and rsync protocol. Both machines ideally should have rsync for this to work.

$ rsync --delete -azvv -e ssh /home/path/folder1/ remoteuser@remotehost.remotedomain:/home/path/folder2
$ rsync --delete -azvv -e 'ssh -p 888' /home/path/folder1/ user@host.remotedomain:/home/path/folder2
$ rsync --delete -azvv -e 'ssh -i /home/tlclab-bastion.pem' ubuntu@13.213.72.65:/drupal10/ /drupal10

One advantage in using the rsync protocol over SSH is that you do not need to use the root password with the --password-file command. You can use arbitrary passwords. However, for this to happen, you need to configure the rsync daemon to allow for this type of connection. More info for Ubuntu.

Running as Rsync as a daemon (Rsyncd) is one way to automating the process.

You can do rsync passwordless if you wish.

One of the most important thing we want to achieve is the permissions are intact.

An explanation of above options to commands:

• --delete deletes files that don't exist on the system being backed up.(Optional)
• -a preserves the date and times, and permissions of the files (same as -rlptgoD). With this option rsync will:
  o Descend recursively into all directories (-r),
  o copy symlinks as symlinks (-l),
  o preserve file permissions (-p),
  o preserve modification times (-t),
  o preserve groups (-g),
  o preserve file ownership (-o), and
  o preserve devices as devices (-D).
• -z compresses the data
• -vv increases the verbosity of the reporting process
• -e specifies remote shell to use

Other options I often use is the exclude option. With this, the files in folders .svn are ignored.

rsync --exclude .svn /home/source/ anoneh@10.20.5.25:/home/anoneh/svg

More options:

 -v, --verbose               increase verbosity
 -q, --quiet                 suppress non-error messages
     --no-motd               suppress daemon-mode MOTD (see caveat)
 -c, --checksum              skip based on checksum, not mod-time & size
 -a, --archive               archive mode; equals -rlptgoD (no -H,-A,-X)
     --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         backup suffix (default ~ w/o --backup-dir)
 -u, --update                skip files that are newer on the receiver
     --inplace               update destination files in-place
     --append                append data onto shorter files
     --append-verify         --append w/old data in file checksum
 -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 tree
 -k, --copy-dirlinks         transform symlink to 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 executability
     --chmod=CHMOD           affect file and/or directory permissions
 -A, --acls                  preserve ACLs (implies -p)
 -X, --xattrs                preserve extended attributes
 -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 modification times
 -O, --omit-dir-times        omit directories from --times
     --super                 receiver attempts super-user activities
     --fake-super            store/recover privileged attrs using xattrs
 -S, --sparse                handle sparse files efficiently
 -n, --dry-run               perform a trial run with no changes made
 -W, --whole-file            copy files whole (w/o delta-xfer 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 remote machine
     --existing              skip creating new files on receiver
     --ignore-existing       skip updating files that exist on receiver
     --remove-source-files   sender removes synchronized files (non-dir)
     --del                   an alias for --delete-during
     --delete                delete extraneous files from dest dirs
     --delete-before         receiver deletes before transfer (default)
     --delete-during         receiver deletes during xfer, not before
     --delete-delay          find deletions during, delete after
     --delete-after          receiver deletes after transfer, not before
     --delete-excluded       also delete excluded files from dest dirs
     --ignore-errors         delete even if there are I/O errors
     --force                 force deletion of dirs 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 end
 -m, --prune-empty-dirs      prune empty directory chains from file-list
     --numeric-ids           don't map uid/gid values by user/group name
     --timeout=SECONDS       set I/O timeout in seconds
     --contimeout=SECONDS    set daemon connection timeout in seconds
 -I, --ignore-times          don't skip files that match size and 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 received 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
     --skip-compress=LIST    skip compressing files with suffix in LIST
 -C, --cvs-exclude           auto-ignore files in 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
 -s, --protect-args          no space-splitting; wildcard chars only
     --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
     --out-format=FORMAT     output updates using the specified FORMAT
     --log-file=FILE         log what we're doing to the specified FILE
     --log-file-format=FMT   log updates using the specified FMT
     --password-file=FILE    read daemon-access 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 dest
     --read-batch=FILE       read a batched update from FILE
     --protocol=NUM          force an older protocol version to be used
     --iconv=CONVERT_SPEC    request charset conversion of filenames
     --checksum-seed=NUM     set block/file checksum seed (advanced)
 -4, --ipv4                  prefer IPv4
 -6, --ipv6                  prefer IPv6
     --version               print version number
(-h) --help                  show this help (see below for -h comment)

Rsync can also be run as a daemon, in which case the following options are accepted:

    --daemon                run as an rsync daemon
    --address=ADDRESS       bind to the specified address
    --bwlimit=KBPS          limit I/O bandwidth; KBytes per second
    --config=FILE           specify alternate rsyncd.conf file
    --no-detach             do not detach from the parent
    --port=PORT             listen on alternate port number
    --log-file=FILE         override the "log file" setting
    --log-file-format=FMT   override the "log format" setting
    --sockopts=OPTIONS      specify custom TCP options
-v, --verbose               increase verbosity
-4, --ipv4                  prefer IPv4
-6, --ipv6                  prefer IPv6
-h, --help                  show this help (if used after --daemon)

To only copy files but no recursive use the filter command.

rsync -a -f"- */" -f"+ *" /home/user/ destination/

More info on rsync.

/folder1 and folder2 In the examples above, folder1 and 2 are placeholders for the directories to be synchronized. Folder1 is the original folder, and 2 is the new folder, or existing one to be brought in sync with the first. Replace them with the folders you'd like. A / was added after folder1 so that only the contents, rather than whole folder, would be moved into the second.