dump – Encrypted Backups to a Remote Server

Dump is a simple command line utility to orchestrate backups. It is built on Duplicity, which is a powerful and flexible utility for managing encrypted backups, however it has a rather heavy user interface. With dump, you specify all the details about your backups once in advance, and then use a very simple command line interface for your day-to-day activities.

Dump is a relatively small python script that designed to be modified to customize it for a particular backup. If you wish multiple backups, you simply copy the dump script and modify each copy for a particular backup.

Generally, you should dedicate a directory to your backups. That directory will hold the dump executable and the archive directory. The archive directory contains Duplicity housekeeping files for the backup. You can place as many of the dump executables as you wish in that directory and they can be configured to share the archive directory.

Backup

Once configured, you would perform your first backup as a full backup:

./dump backup full

After than, you should prefer incremental backups, which you run using:

./dump backup

Manifest

Once a backup has been performed, you can list the files available in your backup using:

./dump manifest

You can list the files that existed on a particular date using:

./dump --date 2015-04-01 manifest

Or, you can list the files that existed 3.5 days ago using:

./dump --date 3D12h manifest

The interval string passed as the date is constructed using an integer followed by one of the following characters s (seconds), m (minutes), h (hours), D (days), W (weeks), M (months), or Y (years). You can combine several to get more resolution.

Restore

You restore a file or directory using:

./dump restore src/verif/av/manpages/settings.py

Use manifest to determine what path you should specify to identify the desired file or directory.

You can restore the version of a file that existed on a particular date using:

./dump --date 2015-04-01 restore src/verif/av/manpages/settings.py

Or, you can restore the version that existed 6 months ago using:

./dump --date 6M restore src/verif/av/manpages/settings.py

Cleanup

You can clean up your remote repository using:

./dump cleanup

This removes any unneeded files Duplicity created files in the remote repository. This is not normally necessary, however it can be helpful if a previous session terminated abnormally.

If you also give a date, any backup sets that only contain files that are older than the given date are deleted:

./dump -d 1Y cleanup

This can reduce the size of your remote repository. Of course after doing this you may not be able to restore files that were deleted before the date you specified.

Help

Information about a variety of topics is provided with the help command.

Use:

./dump help

for a list of topics, and:

./dump help <topic>

for information about a specific topic.

Trouble

If Duplicity is refusing to work for you, run using the verbose flags:

./dump -v -n backup full

Then carefully read the error messages. They should lead you to the problem.

Installing

You generally would not install dump because the executable is tailored to back up a specific directory. Instead you just run it in place. If you would like to backup multiple directories, simply make multiple copies of the dump executable and customize each one.

Before you can use dump you need to install docopt using:

yum install python-docopt (or python3-docopt)

You also need scripts. You can install it or simply copy scripts.py into the dump source directory.

You will also need the inform package from my github account (https://github.com/KenKundert/inform.git) or ‘pip install inform’.

Precautions

You should assure you have a backup copy of the GPG passphrase in a safe place. This is very important. If the only copy of the GPG passphrase is on the disk being backed up, then if that disk were to fail you would not be able to access your backups.

If you keep the GPG passphrase in the dump file, you should set its permissions so that it is not readable by others:

chmod 700 dump

Better yet is to simply not store the passphrase in the dump script. This can be arranged if you are using Abraxas, which is a flexible password management system. The interface to Abraxas is already built in to dump, but its use is optional (it need not be installed).

It is also best, if it can be arranged, to keep your backups at a remote site so that your backups do not get destroyed in the same disaster, such as a fire or flood, that claims your original files. If you do not have, or do not wish to use, your own server, Duplicity offers a number of backends that allow you to place your backups in the cloud (Rackspace, Dropbox, Amazon, Google, etc.). Remember, your data is fully encrypted, so they cannot pry.

Duplicity

Between Duplicity version 0.6.25 and 0.7.05 the way you specify the SSH backend changes. Duplicity provides several different implementations of the SSH backend. The default is paramiko, however it does not support bandwidth limiting. So instead, dump uses the pexpect version. In version 0.6.25 the backend was specified with ‘–ssh-backend pexpect’. In version 0.7.05 it is now specified by adding it to the protocol specification for the remote destination, so ‘sftp://...’ changes to ‘pexpect+sftp://...’.

To address this, dump provides the SSH_BACKEND_METHOD which should be set to ‘option’ for Duplicity version 0.6.25 and lower, and should be set to ‘protocol’ for version 0.7.05 and above.

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