Time machine style backups using rsync

Description

Time Machine style backups with rsync. Tested on Linux, but should work on any platform since this script has no relevant operating system or file system specific dependencies like the original.

Installation

git clone https://github.com/eaut/rsync-time-backup

Usage

tmbackup.sh [OPTIONS] command [ARGS]

Commands:

  init <backup_location> [--local-time]
      initialize <backup_location> by creating a backup marker file.

         --local-time
             name all backups using local time, per default backups
             are named using UTC.

  backup <src_location> <backup_location> [<exclude_file>]
      create a Time Machine like backup from <src_location> at <backup_location>.
      optional: exclude files in <exclude_file> from backup

  diff <backup1> <backup2>
      show differences between two backups.

Options:

  -s, --syslog
      log output to syslogd

  -k, --keep-expired
      do not delete expired backups until they can be reused by subsequent backups or
      the backup location runs out of space.

  --ssh-opt <option>
      pass options to ssh, e.g. '-p 22'

  -v, --verbose
      increase verbosity

  -h, --help
      this help text

local backup example

# setup backup location
tmbackup.sh init /path/to/backup

# backup all files from source except those mentioned in the backup.exlude file
tmbackup.sh backup /path/to/source /path/to/backup /path/to/backup/backup.exclude

An optional exclude file can be added to the backup command that is passed as --exclude-from file to rsync.

+ /path/to/source/.fileA
- /path/to/source/.*
- /path/to/source/junk/

remote backup example

To backup to a remote server you need ssh key-based authentication between client and server. Backup source has to be local.

# destinations must be in the form of <user>@<host>:<directory>
tmbackup.sh backup /path/to/source user@host:/path/to/backup

crontab example

You can log everything to syslog by using "-s" or "--syslog".

# backup /home at quarter past every hour to /mnt/backup
15 * * * * tmbackup.sh -v -s -k backup /home /mnt/backup /mnt/backup/backup.exclude

customize backup retention times

Old backups are automatically expired and purged - default retention times see below. The backup marker file is also used as configuration file for backup retention times.

RETENTION_WIN_ALL=$((4 * 3600))        # within 4 hrs keep all backups
RETENTION_WIN_01H=$((1 * 24 * 3600))   # within 24 hrs keep 1 backup per hour
RETENTION_WIN_04H=$((3 * 24 * 3600))   # within 3 days keep 1 backup per 4 hours
RETENTION_WIN_08H=$((14 * 24 * 3600))  # within 2 weeks keep 1 backup per 8 hours
RETENTION_WIN_24H=$((28 * 24 * 3600))  # within 4 weeks keep 1 backup per day
                                       # thereafter keep the most recent backup of each month

Features

Improvements/changes compared to Laurent Cozic's version

more priority for new backups:
1. expire backups by moving them to an expired folder (fast!)
2. create new backup
3. delete old backups thereafter (slow!, all inodes have to be removed)
shorter backup times:
- minimize inode deletions/creations by reusing expired backups - usually most files/inodes have not changed even compared to older backups
backup.marker file can be used as config file
- more flexible and configurable backup expiration windows
- UTC & local time handling as part of backup.marker config
flexible command line interface, new subcommands and options
- compare to backups, initialize backup marker, ...
- option to log to syslog

Unchanged

Each backup is on its own folder named after the current timestamp. Files can be copied and restored directly, without any intermediate tool.
Files that haven't changed from one backup to the next are hard-linked to the previous backup so take very little extra space.
Safety check - the backup will only happen if the destination has explicitly been marked as a backup destination.
Resume feature - if a backup has failed or was interrupted, the tool will resume from there on the next backup.
"latest" symlink that points to the latest successful backup.

Issues

date command

The date command exists in different flavors. Please check that your operating system is properly supported in the fn_parse_date function.

remote shell

Shells like csh/tcsh have known issues with multiple line quoting. If you are having issues with remote backups, check that your login $SHELL on the remote side is set to either bash or sh.

LICENSE

The MIT License (MIT)

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

asclepius/rsync-time-backup