How do I create a live backup?

I need a live backup to take over if my server fails?

This is something you'll have to build yourself. For the database part, you can use a managed database that is accessibly to both the primary and the live backup.

When failover occurs, the database will be up to date.

However, the mechanics of how/when/why a failover is necessary is a matter for your own creativity. I suggest you start here:

https://www.linode.com/blog/cloud-consulting-services/high-availability-what-you-need-to-know/

I'm not a Linode employee and I don't play one on TV…

-- sw