I can not lose any data or files, so the backup would have to occur at least once an hour (if not more often) and all should be saved for at least 30 days.
DROPLET 1 - CentOS 7.2 X 64 - Uses WHM/cPanel to manage many domains and acts as email server via WHM/cPanel
DROPLET 2 - Ubuntu LEMP on 14.04 - dedicated server for one domain with no adminstrative software like WHM
DROPLET 3 - Debian 8.3 x 64 - dedicated server for one domain with no adminstrative software like WHM
Finally a plan to allow me to determine when I need to expand system resources (DB, CPU, RAM, DISk SPACE)
Please describe your plan in detail.