[CentOS] "power outage"-save / like embedded systems

I would like to setup a small system based on CentOS6 
"power outage"-save as possible. The hardware will be 
switch off by pulling the plug. 

To accomplishing this goal, I would mounting some fs parts 
readonly (e.g. /usr) and thinking about tmpfs for volatile 
parts (e.g. lock, run under var). Additionally "optimize" 
some vm.dirty_* kernel- and fs/ext4 parameters. /persistent 
would be used with jffs2 on a CF card. So far the theory.

Does anyone have some experience with such type of systems?
Any pointer to pitfalls are welcome.

--
Thanks
LF