Using rsnapshot for easy backups

Author: Solène

Date: 10 January 2020

Tags: openbsd

NIL## Introduction

rsnapshot is a handy tool to manage backups using rsync and hard links on the

filesystem. rsnapshot will copy folders and files but it will skip duplication

over backups using hard links for files which has not changed.

This kinda create snapshots of your folders you want to backup, only using

rsync, it's very efficient and easy to use, and getting files from backups is

really easy as they are stored as files under the rsnapshot backup.

Installation

Installing rsnapshot is very easy, on most systems it will be in your official

repository packages.

To install it on OpenBSD: `pkg_add rsnapshot` (as root)

Configuration

Now you may want to configure it, in OpenBSD you will find a template in

`/etc/rsnapshot.conf` that you can edit for your needs (you can make a backup

of it first if you want to start over). As it's stated in big (as big as it can

be displayed in a terminal) letters at the top of the configuration sample

file, you will see that things must be separated by TABS and not spaces. I've

made the mistakes more than once, don't forget using tabs.

I won't explain all options, but only the most importants.

The variable `snapshot_root` is where you want to store the backups. Don't put

that directory in a directory you will backup (that will end into an infinite

loop)

The variable `backup` is for telling rsnapshot what you want to backup from

your system to which directory inside snapshot_root

Here are a few examples:

backup /home/solene/ myfiles/

backup /home/shera/Documents shera_files/

backup /home/shera/Music shera_files/

backup /etc/ etc/

backup /var/ var/ exclude=logs/*

**Be careful when using ending slashes to paths, it works the same as with rsync**.

`/home/solene/` means that into target directory, it will contains the content

of `/home/solene/` while `/home/solene` will copy the folder solene within the

target directory, so you end up with target_directory/solene/the_files_here.

The variables `retain` are very important, this will define how rsnapshot keep

your data. In the example you will see alpha, beta, gamma but it could be hour,

day, week or foo and bar. It's only a name that will be used by rsnapshot to

name your backups and also that you will use to tell rsnapshot which kind of

backup to do. Now, I must explain how rsnapshot actually work.

How it work

Let's go for a straighforward configuration. We want a backup every hour on the

last 24h, a backup every day for the past 7 days and 3 manuals backup that we

start manually.

We will have this in our rsnapshot configuration

retain hourly 24

retain daily 7

retain manual 3

but how does rsnapshot know how to do what? The answer is that it doesn't.

In root user crontab, you will have to add something like this:

run rsnapshot every hour at 0 minutes

0 * * * * rsnapshot hourly

run rsnapshot every day at 4 hours 0 minutes

0 4 * * * rsnapshot daily

and then, when you want to do a manual backup, just start `rsnapshot manual`

Every time you run rsnapshot for a "kind" of backup, the last version will be

named in the rsnapshoot root directory like hourly.0 and every backups will be

shifted by one. The directory getting a number higher than the number in the

`retain` line will be deleted.

New to crontab?

If you never used crontab, I will share two important things to know about it.

Use MAILTO="" if you don't want to receive every output generated from scripts

started by cron.

Use a PATH containing /usr/local/bin/ in it because in the default cron PATH it

is not present. Instead of setting PATH you can also using full binary paths

into the crontab, like /usr/local/bin/rsnapshot daily

You can edit the current user crontab with the command `crontab -e`.

Your crontab may then look like:

PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/X11R6/bin:/usr/local/bin:/usr/local/sbin

MAILTO=""

comments are allowed in crontab

run rsnapshot every hour at 0 minutes

0 * * * * rsnapshot hourly

run rsnapshot every day at 4 hours 0 minutes

0 4 * * * rsnapshot daily