Come trasferire files in modo efficiente con RSYNC

In passato, per trasferire dei files su un server remoto, usavo FTP o SSH. Recentemente, ho scoperto rsync un programma open source, in grado di svolgere questo compito in maniera estremamente veloce ed efficiente. Rsync usa la codifica delta per trasferire e sincronizzare i files in modo veloce ed incrementale …

Pubblicato da Roberto Fusi in Internet. Aggiornato .
Lunghezza testo: 1472 parole. Stima tempo lettura: 6 minuti.
Tag: programmi. .

In passato, per trasferire dei files su un server remoto, usavo FTP o SSH. Recentemente, ho scoperto rsync un programma open source, in grado di svolgere questo compito in maniera estremamente veloce ed efficiente.

Rsync usa la codifica delta per trasferire e sincronizzare i files in modo veloce ed incrementale; infatti, il programma trasferisce solo le differenze fra i files nella posizione di origine e quella di destinazione.

Le funzionalità del programma includono:

  1. l’aggiornamento di files e cartelle
  2. mantenimento dei link simbolici, proprietà, permessi ed altri attributi dei files
  3. non richiede particolari privilegi per l’installazione
  4. può trasportare i pacchetti dei file fruttando rsh, ssh e connessini dirette
  5. supporta trasferimenti con connessioni anonime

Ho installato cwRsync, una distribuzione di rsync per sistemi Windows. Il software può essere scaricato gratuitamente come archivio compresso .ZIP; ho estratto i files nella cartella di sistema “Programmi (x86)” ottenendo questi files e cartelle:

Directory di C:\Program Files (x86)\cwRsync_5.5.0_x86_Free

28/04/2017  16:20    <DIR>          .
28/04/2017  16:20    <DIR>          ..
24/04/2017  17:38    <DIR>          bin
28/04/2017  16:08             1.679 cwrsync.cmd
28/04/2017  16:20                 0 cwRsync.txt
24/04/2017  17:38             1.108 README.cwrsync.txt
24/04/2017  17:38             4.170 README.rsync.txt
               4 File          6.957 byte

 Directory di C:\Program Files (x86)\cwRsync_5.5.0_x86_Free\bin

24/04/2017  17:38    <DIR>          .
24/04/2017  17:38    <DIR>          ..
24/04/2017  17:38         2.028.061 cygcrypto-1.0.0.dll
24/04/2017  17:38           110.109 cyggcc_s-1.dll
24/04/2017  17:38         1.034.269 cygiconv-2.dll
24/04/2017  17:38            42.013 cygintl-8.dll
24/04/2017  17:38            41.501 cygpopt-0.dll
24/04/2017  17:38            12.829 cygssp-0.dll
24/04/2017  17:38         3.488.471 cygwin1.dll
24/04/2017  17:38            84.519 cygz.dll
24/04/2017  17:38           429.582 rsync.exe
24/04/2017  17:38           413.710 ssh-keygen.exe
24/04/2017  17:38           694.286 ssh.exe
              11 File      8.379.350 byte

     Totale file elencati:
              15 File      8.386.307 byte

Ho controllato il file README.cwrsync.txt ed ho poi aggiunto il percorso “C:\Program Files (x86)\cwRsync_5.5.0_x86_Free\bin” alla variabile ambiente PATH.

Impostazione PATH

A questo punto, ho aperto il Prompt dei comandi ed ho fatto una prova; ho eseguito il comando “rsync —help” ed ho ottenuto il seguente risultato.

rsync  version 3.1.2  protocol version 31
Copyright (C) 1996-2015 by Andrew Tridgell, Wayne Davison, and others.
Web site: http://rsync.samba.org/
Capabilities:
    64-bit files, 64-bit inums, 32-bit timestamps, 64-bit long ints,
    socketpairs, hardlinks, symlinks, IPv6, batchfiles, inplace,
    append, ACLs, no xattrs, iconv, symtimes, prealloc

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
     --info=FLAGS            fine-grained informational verbosity
     --debug=FLAGS           fine-grained debug verbosity
     --msgs2stderr           special output handling for debugging
 -q, --quiet                 suppress non-error messages
     --no-motd               suppress daemon-mode MOTD (see manpage 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         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
     --append-verify         like --append, but with 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 source tree
     --munge-links           munge symlinks to make them safer (but unusable)
 -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           affect file and/or directory permissions
 -A, --acls                  preserve ACLs (implies --perms)
 -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
 -J, --omit-link-times       omit symlinks from --times
     --super                 receiver attempts super-user activities
 -S, --sparse                handle sparse files efficiently
     --preallocate           allocate dest files before writing them
 -n, --dry-run               perform a trial run with no changes made
 -W, --whole-file            copy files whole (without 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 the remote machine
     --existing              skip creating new files on receiver
     --ignore-existing       skip updating files that already exist on receiver
     --remove-source-files   sender removes synchronized files (non-dirs)
     --del                   an alias for --delete-during
     --delete                delete extraneous files from destination dirs
     --delete-before         receiver deletes before transfer, not during
     --delete-during         receiver deletes during the transfer
     --delete-delay          find deletions during, delete after
     --delete-after          receiver deletes after transfer, not during
     --delete-excluded       also delete excluded files from destination dirs
     --ignore-missing-args   ignore missing source args without error
     --delete-missing-args   delete missing source args from destination
     --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
     --usermap=STRING        custom username mapping
     --groupmap=STRING       custom groupname mapping
     --chown=USER:GROUP      simple username/groupname mapping
     --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 in size and mod-time
 -M, --remote-option=OPTION  send OPTION to the remote side only
     --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
     --skip-compress=LIST    skip compressing files with a suffix in LIST
 -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
 -s, --protect-args          no space-splitting; only wildcard special-chars
     --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=RATE          limit socket I/O bandwidth
     --outbuf=N|L|B          set output buffering to None, Line, or Block
     --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
     --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 (-h is --help only if used alone)

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, appare dunque un programma molto utile e potente per sincronizzare i files su server remoti ed altre risorse locali (per esempio, un hard disk per fare un backup). Fino ad oggi ho sperimentato le seguenti applicazioni:

  1. x sincronizzare files e cartelle fra una posizione di origine ed una di destinazione

    rsync -vru [percorso_origine] [percorso_destinazione]

  2. x aggiornare il file del sito sul server web

    rsync -cpthrvz —delete —exclude “.” —exclude “D” —exclude “S” —exclude “_” —exclude “S” —exclude “t” —exclude “o” —exclude “r” —exclude “e” —chmod=Du=rwx,Dgo=rx,Fu=rw,Fgo=r —rsh=’ssh -p 22 ‘ [percorso_origine] [user]@[ip_server]:[percorso_destinazione]

Si noti l’opzione “—chmod=Du=rwx,Dgo=rx,Fu=rw,Fgo=r” usata nel secondo esempio, che imposta correttamente gli attributi di cartelle e files quando vengono copiate da Windows al web server basato su sistema Unix.

Riferimenti

  1. rsync
  2. cwrsync
  3. WikiPedia rsync
  4. WikiPedia Codifica delta
  5. WikiPedia chmod

Libri suggeriti

Guide gratuite:

  1. Guida Rsync di debianizzati.org

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IpeRteSTi é un blog curato da Roberto Fusi. Raccoglie suggerimenti ed esperienze personali riguardo Internet, Web Development e la Digital Economy.

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