Incremental backup for directory using rdiff-backup

Published on: 14th Oct 2022

Overview

This utility provides the following features:

Backup the directory or selected file to local or remote storage.
Incremental backup will be created. This means, only the differences in the old and new files (i.e., "delta") will be send to the destination.
It works with SSH (i.e., a secure shell communcation).
This solution works on Windows, Linux, Unix and MacOS.
Able to restore a selected file or directory.
Able to remove the old backups.

Requirements

Both server and client must install rdiff-backup.

For Ubuntu, run the following command to install this utility before backing up the data from your computer.
```
sudo apt install rdiff-backup
```
For Windows, download the EXE from the following site,

https://github.com/rdiff-backup/rdiff-backup/releases

Operations on Windows platform with Powershell

First, I copied rdiff-backup.exe to d:\temp3 directory. This is to simplify the testing to this utility. Once you have confirmed that it met your expectation, you may copy the exe to c:\windows\system32 directory to make this command accessible from anywhere in your computer.
Backup a directory,
```
.\rdiff-backup -v5 backup .\src .\bak
```
Backup 'src' directory to another server at 'bak' directory (/home/user1/bak),
```
.\rdiff-backup -v5 backup .\src user1@your-domain.com::bak
```
Notes: it's advisable to setup the SSH key-based authentication to simplify the server access.

To restore a directory to a different location,

.\rdiff-backup -v5 restore .\bak .\src-restored

To view the incremental changes,
```
.\rdiff-backup list increment .\bak
```

To remove an older increments,

.\rdiff-backup remove increments --older-than 2W user1@your-domain.com::/remote-dir
.\rdiff-backup remove increments --older-than 7D .\bak
.\rdiff-backup remove increments --older-than 4B .\bak

Where:

2W is 2 weeks.
7D is 7 days.
4B is 4 backup.

Setup for SSH with key authentication

To backup files (in Windows) to a remote backup server, please follow the steps below:
1. Install openSSH client.
  
  For Windows 10 or Windows 2019,
```
Add-WindowsCapability -Online -Name OpenSSH.Client*
```
  For Winwdows 2012R2 or 2016, download the files from the following site,
  
  https://github.com/PowerShell/Win32-OpenSSH
  
  Alternatively, install PuTTY from the following site,
  
  https://www.putty.org/
2. Then, run PowerShell console.
3. Goto user's home directory.
4. Create .ssh directory,
```
cd ~
mkdir .ssh
cd .ssh
```
5. Generate key pairs for SSH using OpenSSH for Powershell,
```
ssh-keygen
```
  Alternatively, you may use puttygen.exe program to generate the key pairs (id_rsa and id_rsa.pub) and saves the files into .ssh directory.
  
  Notes:
  - Please leave blank for the passphrase so that you can ease the backup process. By defualt, it generates a file id_rsa and id_rsa.pub
6. Copy id_rsa.pub to the backup server,
```
scp id_rsa.pub user1@your-domain.com:authorized_keys
```
  This will copy the file from the local server to the backup server (your-domain.com) and place the file into 'user1' home directory.
7. Logon to the backup server (Ubuntu server in this example).
8. Move the 'authorized_keys' file to '.ssh' directory.
```
cd /home/user1
sudo mkdir .ssh
sudo mv authorized_keys .ssh/authorized_keys
```
Once the public key (id_rsa.pub) has been uploaded to the backup server, you will be able to back up the files to a remote server without entering your password.

For Powershell,
```
cd d:\temp3
.\rdiff-backup -v5 backup .\src user1@your-domain.com::bak
```
In DOS prompt,
```
rdiff-backup -v5 backup d:\temp3\src user1@your-domain.com::bak
```

References

Project site

https://rdiff-backup.net/
Source code

https://github.com/rdiff-backup/rdiff-backup

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Author

Lau Hon Wan, software developer.