How to setup automated backups to SSH server with Synology DiskStation

As a best practice, it’s great great to have your data in more than one location. I use my Synology Diskation as a local network file server at my home. The reality is something can happen and I lose all my important data in that little box. From a BBQ, a birthday party, or maybe the house just burns down and now all my data is gone. Unfortunately my network rack at home will never be as secure as a network rack in a data center. So, backup your data because that’s much easier to do rather than trying to restore from no backup. Makes logical sense right? Derp.

Requirements

  • Basic shell knowledge.
  • A remote server that you can SSH into.

Why not use the “Backup & Replication” plugin?

The Backup & Replication module does not have a way to specify my remote server’s rsync port. The default is 22 but my host runs on port 2222.

1. Enable SSH on your Synology Box

First things first. Enable SSH on your Synology box if you haven’t already done so and log in (via ssh).

2. Generate SSH keys

We’ll need to generate a pair of keys here so rsync is not prompted for your password when it runs otherwise this defeats the purpose of automation. To do this, run the following command:

ssh-keygen -v -t rsa -f ~/.ssh/backup -P ""

This will generate /root/.ssh/backup and /root/.ssh/backup.pub.

3. Copy your public key to the remote server

Login to your remote server and put the contents of /root/.ssh/backup.pub from your Synology box to ~/.ssh/authorized_keys on your remote box. If this file on your remote box already exists, then just append the contents to it rather than overwriting it. If this file does not exist, then create it.

If you create it manually then make sure the following files have the following permissions otherwise SSH will not allow you to use

  • 0700: ~/.ssh
  • 0644: ~/.ssh/authorized_keys

You should be able to SSH from your Synology Diskation to your remote machine without specifying a password. Here is an example command:

ssh username@home -i /root/.ssh/backup -v

The -i command tells SSH which private key to use and the -v would make the program verbose.

4. Configure rsync and crontab

Last but not least, we need to add a line in our crontab configuration to run rsync at a specific time. Here is an example of mine:

0   0   *   *   *   root    rsync -avztP --delete --inplace /volume1/photo/ username@host:/backups/glitch/photo -e "ssh -p 2222 -i /root/.ssh/backup" --exclude ".DS_Store" --exclude "@eaDir" --exclude ".apdisk"
0   1   *   *   *   root    rsync -avztP --inplace /volume1/manuals/ username@host:/backups/glitch/manuals -e "ssh -p 2222 -i /root/.ssh/backup" --exclude ".DS_Store" --exclude "@eaDir" --exclude ".apdisk"
0   2   *   *   *   root    rsync -avztP --inplace /volume1/surveillance/ username@host:/backups/glitch/surveillance -e "ssh -p 2222 -i /root/.ssh/backup" --exclude ".DS_Store" --exclude "@eaDir" --exclude ".apdisk"
0   3   *   *   *   root    rsync -avztP --inplace /volume1/video/ username@host:/backups/glitch/video -e "ssh -p 2222 -i /root/.ssh/backup" --exclude ".DS_Store" --exclude "@eaDir" --exclude ".apdisk"
0   4   *   *   *   root    rsync -avztP --inplace /volume1/applications/ username@host:/backups/glitch/applications -e "ssh -p 2222 -i /root/.ssh/backup" --exclude ".DS_Store" --exclude "@eaDir" --exclude ".apdisk"
0   5   *   *   *   root    rsync -avztP --delete --inplace /volume1/zappiti/ username@host:/backups/glitch/zappiti -e "ssh -p 2222 -i /root/.ssh/backup" --exclude ".DS_Store" --exclude "@eaDir" --exclude ".apdisk"

It’s important to note that each field must be indented by a tab (not a space) and the user must be root. If you configure this another way then the Synology server will erase the entry when you reboot the machine. Here are some configuration options for reference.

Put your configuration in /etc/crontab. You can use nano if you’re on DSM 4 or vi if you’re on DSM 5.

Lastly, we need to restart the cron daemon to take note of our changes. The command is restart crond on DSM 5 machines and /usr/syno/sbin/synoservice --restart crond on DSM 4 machines.

Jul 12, 2014 Servers

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Richard S.