Recently, I was introduced to rsnapshot, which is a great tool for simple backup. It uses rsync to backup files. And it also uses hard links, so it can provide hourly 'snapshots' while it stores unchanged files only once. I wanted to use rsnapshot for backing up the files I have on my website at my hosting providers' server, but sadly enough, my hosting provider doesn't provide rsync support - damn cheap hosting ;-(.

Luckily I do have ssh access to my files, and using sshfs you can work around the missing rsync on the server. (Probably much slower than with rsync, and I am also unable to keep the permissions of the files, but hey - it's better than nothing.)

If your home server is Debian-based, you can install the required packages using apt:

  apt-get install sshfs fuse-utils rsnapshot

(otherwise use yum or pacman or whatever tool your distribution provides.)

First you want to make sure that the root user of your home server can ssh to my web server without password, so that the remote file system can automatically be mounted onto your own computer. This can be done with public key authentication.

Check whether the root user has a file ~/.ssh/id_rsa.pub in it's home directory. If the file is there, that's great. If not, you shoulde generate it, issuing the command

  ssh-keyhgen -t rsa

Don't enter a password, and store the file on the default location.

Now you have to add the contents of the id_rsa.pub on your computer at home to the ~/.ssh/authorized_keys file in your home directory on the remote web server. If the remote file doesn't exist, just create it.

This should enable you ssh'ing from your computer at home to your web server without having to enter a password.

The following step is using sshfs to access your remote files via a mount point on your home server. Create a mount point:

  mkdir /mnt/webserver

and add a line to /etc/fstab: (change remote username, server name and homedir to your situation)

  sshfs#remoteuser@your.webserver.org:/your/homedir /mnt/webserver fuse defaults,idmap=none,uid=root,gid=root   0 0

If you now enter the command

  mount /mnt/webserver

you should be able to find your remote files en directories under the /mnt/webserver mount point. The remote files have root as user and group, this is OK since rsnapshot will be run as root.

The next step is configuring rsnapshot. Open /etc/rsnapshot.conf, and read the part about trailing slashes and tabs: if you change the configuration file, you should put a slash after each directory name, and use tabs between elements on a line. So make sure your text editor saves tabs as tabs!

Search the line that starts with rsnapshot_root, and change it to

  snapshot_root   /path/to/backup/location/

Important:

• Make sure to put a tab between the parts, and add a trailing slash
• The file system of rsnapshot_root should support hard links (ext3, ext4 are fine)

Then search for lines starting with 'backup'. There are some examples for backing up /home, /etc and /usr/local. If you want to back up them as well, then you can leave them. If not, just comment them out. The important thing is adding this line:

  backup  /mnt/webserver/        localhost/

If you now issue the command

  rsnapshot hourly

a folder hourly.0 will be created under your rsnapshot root, containing a copy of the files on your webserver. If after that you type

  rsnapshot hourly

again, this folder is renamed to hourly.1, and a new folder hourly.0 is created with the current files on your server. This second backup won't take a lot of disk space though, because the files which are the same in hourly.0 and hourly.1 will only be stored once on the file system.

Now open /etc/cron.d/rsnapshot. If you uncomment the cron lines in there, rsnapshot will be run automatically. The monthly backups will be taken the first of the month, the weekly backups on wednesday, the daily backups every morning at 3:30, and the hourly backups every 4 hours.

Now I still have to figure out how I can backup my database. I don't have command line mysql on the server, so I will have to use the mysql web interface. I will keep you informed when I get this working automatically :)