What are the main criteria for choosing server hardware for a busy site?

Question

Iron

There is a site on which attendance is growing and will grow intensively. Used nginx + php-fpm + mysql + redis. Now it consists of two servers - 1 for the front, the second for the base. All this in the form of vds. We want to purchase 2 physical servers according to the same principle (front + back). In this connection, the question is what are the critical places for 1 and the other server. As for the front, we think a more powerful processor is needed, in the xeon 2630v3 region, maybe even 2. 64GB RAM. Hard drives are probably not so critical here. As for the back, we are also thinking about the same processors, since there will also be a lot of cache in the radish and work with temporary tables. How justified is this choice and what are generally more critical places for the front and back? For example, for nginx-php, in theory, they like a good percentage.

Answer 1

on the frontend, php loves the cpu, if there are not many statics, then ssd is not needed, let everything be cached by nginx
for the second - the cpu depends on the complexity of queries in the database and their number, memory - it is desirable so that the entire database fits into it.
Also pay attention to the traffic between the frontend and the backend, there are cases (software or tsms such) when gigabit is not enough.

Answer 2

PHP is a percent, a database is a RAM, if we really simplify it. Therefore, they answered you correctly above - we buy processors for the frontend, we buy a maximum of RAM for the database, so that ideally it all fits where it is not enough - we put an SSD, that's the whole recipe itself.

Answer 3

I agree with Vladimir and Valentin. it is worth thinking about raid10 if the box office allows. How it was for me. Might be useful