myterminal / ursa

My opinionated data backup and retrieval system

ursa-major

My opinionated data backup and retrieval system

Purpose

(coming soon...)

Requirements

Hardware

The system has been designed with an external storage drive in mind with the following data volumes:

1. /dev/sdb1 - Backup volume 1
2. /dev/sdb2 - Backup volume 2
3. /dev/sdb3 - Backup volume 3
4. /dev/sdb4 - Live volume hosting ursa

The above specification assumes that the external drive has been identified as /dev/sdb block device.

Software

ursa is a simple set of shell scripts with the least number of external dependencies that it sets up to be able to perform its operations, which includes regular backups, updates, and eventual data retrieval by a trusted family member or inheritor.

Suggested Volume Setup

Set up partitions

cfdisk /dev/sdb

Partitions:

1. /dev/sdb1 - backup partition 1
2. /dev/sdb2 - backup partition 2
3. /dev/sdb3 - backup partition 3
4. /dev/sdb4 - auxiliary partition

Format backup partitions with LUKS

cryptsetup -y -v luksFormat --type luks1 /dev/sdb1
cryptsetup -y -v luksFormat --type luks1 /dev/sdb2
cryptsetup -y -v luksFormat --type luks1 /dev/sdb3

Format auxiliary partition with EXT4

mkfs.ext4 /dev/sdb4

Open backup partitions to create an EXT4 underneath

cryptsetup open /dev/sdb1 vault-a
cryptsetup open /dev/sdb2 vault-b
cryptsetup open /dev/sdb3 vault-c
mkdir /mnt/vault-a /mnt/vault-b /mnt/vault-c
mount /dev/mapper/vault-a /mnt/vault-a
mount /dev/mapper/vault-b /mnt/vault-b
mount /dev/mapper/vault-c /mnt/vault-c
chmod 777 -R /mnt/vault-a /mnt/vault-b /mnt/vault-c
mkfs.ext4 /dev/mapper/vault-a
mkfs.ext4 /dev/mapper/vault-b
mkfs.ext4 /dev/mapper/vault-c
cryptsetup close vault-a
cryptsetup close vault-b
cryptsetup close vault-c

Unmount the auxiliary partition

udisksctl unmount -b /dev/sdb4
udisksctl power-off -b /dev/sdb4

Install a graphical Linux distribution on the fourth volume, and deploy ursa on it. Follow the next section on deploying ursa. Preferably enable running sudo commands without a password.

Setup

To prepare the environment with external dependencies, run:

make setup

In order to set ursa on an external storage drive, clone it to a local directory, and run the following command:

./ursa-deploy

You will be prompted to enter a location to the fourth live volume on the target drive. Once a location is provided, and if everything goes as expected, you should be able to see the commands deployed to the specified device.

Usage

Retrieving Data

If you simply need to retrieve data from the three data volumes, run:

./ursa-retrieve

You should be presented with three file explorer windows for the three decrypted data volumes, each having the same exact data.

Regular Backups

ursa has been designed to work with three sets of identical data volumes. It is recommended to run a replication cycle at regular intervals to avoid data loss. The reason for having thee data volumes is that if during a replication cycle, a volume has been identified with issues, another one can be used for the current cycle, and the problematic volume could still be repaired from one of the two working volumes.

To start a backup, simply run:

./ursa-backup

The scripts automatically unlocks the vaults, identify the newest and the oldest replicated volume, and the user is suggested to use the former to replicate the latter. This way, the oldest replicated volume becomes the newest for the next cycle, and all the three volumes get checked for data integrity every third replication cycle. ursa maintains the timestamp using an empty file named .ursa-tag at the root of each data volumes.

Removing the Backup Drive

Removing the backup drive can be performed using a simple command:

./ursa-remove

Updating ursa

In order to update ursa on the backup drive, simply run:

./ursa-update

External Dependencies

• cryptsetup
• udisks2
• meld