Best way to do a VPS Backup (Ubuntu)

[apinto]

Hello,
I've been using Sentora on a VPS hosted with OVH.
So far, so good, it still has a long path to walk but sentora is going at a very good rhythm, Good Work!

Backups
I do know Sentora has a backup system, but that is only for sentora files and configs.
My question is: What is the best way to backup a Ubuntu 14.04 VPS?


Please consider the following:

• It's a relatively limited VPS, I do not have the possibility to make backups from another disk (with the system offline).
  
• My goal is to be able to easily restore the system in case of failure or to be able to move to another server, this includes Ubuntu user configs, Installed Packages, Sentora (inc Apache, Bind9 and other components of Sentora) and everything else I may not be taking in consideration.
  
• (opcional) Backups would be done to my local machine, so they will not require a lot of free space on the VPS.
  

What I have already tried:

• rsync Was a good option, however it has problems with crucial system files that are in use.
  
• .tar user and config files and save a installed packages list, also a good option, probably my best chance at this moment; however I feel hard to know what to backup/restore and I would like a more automated solution.
  

I did searched the forum, and yes there are similar threads, however I felt that they either went into very specific use cases or did not got an appropriate solution.

Note: To thank the community for helping me with this I will make a detailed tutorial, here on Sentora Forum, with a How To Properly Backup your VPS Server.

Thank you in advance for the time you may spend helping me.

Kind Regards,
António Pinto