Here I like to show you my idea of a redundancy solution.
After managing a LAMP for a few years with a solid RAID solution I came to the idea that not only the disks are a risc, but all hardware is.
Also I wanted to move to a enery-friendly solution: low-power cpu's that don't need a cooling fan.
I set up a system of two (or more) redundant fanless mini pc's that can run the different elements of a LAMP.
Any minipc or virtual server can run as a 'brick'.
I split the functions of the LAMP in a few services:
Some services run always on any brick: ntp, cups