Brandysnap is (yet another) script that uses rsync to create snapshot backups of files and directories.
It is designed to be flexible and robust. In particular, it copes well with situations where snapshots are not created as regularly as they should be. This can be for a variety of reasons -- hardware failure, operator failure, weekends, holidays, someone forgot to plug in the external USB drive, etc.
Rather than assigning 'importance' to snapshots according to when they were made (for example, keeping Friday afternoon backups for longer than Tuesday morning ones), it looks at what snapshots exist and decides if any can be deleted. If the Friday afternoon backup is missing, it will keep the nearest one it can find.
The basic rule is 'backup first, ask questions later'. Brandysnap assumes that snapshots (other than the first one) are cheap -- in both time and space. In other words, making a snapshot is quick, and uses relatively little disk space because of the use of hard links.
Brandysnap should be run regularly, via cron or something similar. It creates a new snapshot each time it is run (usually). Then it looks at all existing snapshots to see if any old snapshots can be deleted because they are no longer required, as defined by the configured 'specification'.
It does everything via rsync, which means that either the source or the destination can be 'remote' (i.e. accessed via SSH or similar). That also means that, if root access is required, it only has to be granted specifically for rsync, not for the whole of brandysnap.
It ignores anything other than files and directories, but preserves hard and soft links.
It handles multiple sources and directories in one run. The configuration file can have 'sections' to ensure that, for example, exclusions are applied to the correct source, and options for tweaking remote rsync access can be tailored to each site.
The things it doesn't do are compression and deduplication on the destination. There are no plans to include those features: they belong in the filing system. btrfs, for example, already includes compression, and may do deduplication one day. Nor does Brandysnap do encryption.
Brandysnap has been developed on and runs on Linux. I have heard that it also runs on Mac OS X (at least a previous version did). Work to let it run on Windows in the Cygwin environment is under way, and is included from version 0.2.19.
It requires Perl 5 version 5.10.1 or later, and the following non-core modules:
It also requires rsync, which should available in your version of Linux. Brandysnap has been developed with rsync version 3.0.7 to 3.1.0. It should work with any version of rsync that has the '--link-dest' option.
There is not (yet) an installation script or package: brandysnap is a single Perl script which just has to be run. All you need to do is
Download the script and all the related files by clicking on the 'Downloads' button on https://github.com/StarsoftAnalysis/brandysnap and unpack the files into a suitable directory on your computer.
Make sure you've got rsync and the necessary Perl modules as described above.
Use a text editor to create a configuration file: refer to the documentation (i.e. brandysnap.html or brandysnap.pod) for details.
Run the script, with a command something like this:
./brandysnap --conf brandysnap-test1.conf --dry-run
I have ideas for a few brandysnap-related scripts that would facilitate searching for versions of backed-up files, restoring selected files from brandysnap snapshots, etc.
But first I need to restructure some of the code into a Perl module that the new scripts could access.
This is part of the brandysnap documentation.
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Last modified: 29 August 2014