Snapman

Snapman is a backup program based on the ability of Btrfs file system to capture snapshots of subvolumes.

When you run snapman it will read its configuration file and then it will make backups (snapshots) of indicated subvolumes at desired frequency until reach a defined quota. If quota was reached, then it will remove the older backup before to make a new one to keep the number of backups indicated in quota.

Backups are only performed if there are changes in the indicated subvolume from previous backups.

Snapman will run periodically if you use the --daemon command line option.

Backups are stored in a directory specified in the configuration file.

Since version 1.0a Snapman has an integrated GUI interface. It can be activated using the --gui command line option.

For each subvolume that you want to backup you must to write at least an entry in the configuration file (in the easy .ini format).

Snapman accepts command-line options to manage snapshots.

For futher details, read the included documentation:

• Snapman manual, for the manual.

• Configuration manual, for the manual of configuration file syntax.

When the program is installed, all the documentation are available at /usr/share/doc/snapman. And the manuals with:

    man snapman

And, for configuration file syntax:

    man 5 snapman

Usage

First of all edit the configuration file at /etc/snapman.ini. A default one is supplied as example. Alternatively you can use the --sample command line option to generate one:

    # snapman --sample > /etc/snapman.ini

Then edit /etc/snapman.ini at your preferences. You can edit [DEFAULT] section, but not change the name DEFAULT. It is essential to the right working of the program, due to the other sections inherit properties from it.

You can read man 5 snapman to a complete reference of configuration file format.

We'll go to show a little example. In it we make snapshots for the root filesystem and the /home directory.

    $ cat /etc/snapman.ini
    [DEFAULT]
    subvolume = /
    frequency = 1d
    quota = 30
    readonly = True
    enabled = True
    timestamp = %Y%m%d-%H%M%S
    umask = 022

    [/snapshots]

    [/home/snapshots]
    subvolume = /home

The section name (the path inter []) is the directory where snapshots will be stored.

Each section name has some values. There is a section, named [DEFAULT]. This is used for other sections for get default values, if they are not configured in itself.

Command line mode

Execute as root:

    # snapman

The program will create two snapshots. One for each subvolume especified in every section:

    $ ls /snapshots /home/snapshots
    /snapshots:
    20171025-084416

    /home/snapshots:
    20171025-084416

In the case of [/snapshots] section the subvolume option was inherit from [DEFAULT] section.

If we execute again snapman no action will be runned, due to the frequency option is 1d (one day). Only when the difference is greater than one day would make a new snapshot.

When the number of snapshots is greater than the specified by quota option the older snapshot will be deleted and a new one will be created.

The readonly option makes readonly snapshots and the enabled option allows to disable this section, without delete snapshots. Both options accept boolean values: True, False, 0, 1, on, off.

The timestamp option is the name of snapshot. See https://docs.python.org/3/library/datetime.html#strftime-strptime-behavior for a complete documentation of this format.

The umask value set the umask value for directory creation.

Graphic mode

Execute as root:

    # snapman --gui

Or search the application in your desktop menu.

Daemon mode

Rather than executing manually every certain time, we can use the --daemon command line option:

    # snapman --daemon

And then the program will make copies when necessary to meet the indicated frequency.

For that, a systemd service is included. Just start and enable it:

    # systemctl start snapmand
    # systemctl enable snapmand

Or, if you do no use systemd, add a line like snapman --daemon to your /etc/rc.local or whatever it is that uses your startup system.

One shot service

If you only want to make a single copy each time the system is started (if necessary), instead of using the snapmand.service, start and enable snapman.service (without the final d). This can be useful for saving copies of systems that have successfully started.

    # systemctl start snapman
    # systemctl enable snapman

Command line options.

Snapman program allows to manage snapshots by command line. Here some examples.

To show all command line options:

    $ snapman --help

A list of managed sections:

    $ snapman --sections

A list of snapshots of a section:

    $ snapman --section-snapshots /home/snapshots

Show information of a section:

    $ snapman --section-info /home/snapshots

Delete all snapshots of a section:

    # snapman --section-clean /home/snapshots

Force creation of a new snapshot for section:

    # snapman --section-newsnapshot /home/snapshots

To show additional information when performing actions use --verbose option.

There are more command line options. Please refer to man snapman for a complete and updated guide.

Installation

You can choose between different installation methods.

Classic method

• Build and install:

    $ make
    # make install
  

• Uninstall:

    # make uninstall
  

Arch Linux package

• Build and install:

    $ make arch_pkg
    # pacman -U package_name.pkg.tar.xz
  

• Uninstall:

    # pacman -Rsc snapman
  

Debian package

** Sorry. The Debian package building will not be supported until the stable version is reached. **

• Build and install:

    $ make debian_pkg
    # dpkg -i package_name.deb
  

• Uninstall:

    # apt purge snapman