DB performance comparison: How to install 2 different versions of mysql on the same server?

Question

MySQL

Given: the following server is available
Processor: Intel(R) Xeon(R) CPU E5-2430 0 @ 2.20GHz - 2 pieces
RAM: 96Gb
Drives: SSD 512Gb - 2 pieces
OS: Ubuntu 12.04.5 LTS x64 Upgraded
on the server nginx + php-fpm + mysql 5.5
+ CMS DLE (v 10.2) throws fantastically heavy and unoptimized (and sometimes I would even say that fantastically idiotically unoptimized) requests (alas, there is no way to change the CMS now) .
Problem: at peak loads, mysql simply physically kills 24 threads, reaching the load average of about 50-100.
In mysql-slow.log, queries periodically skip, lasting about 4-15 seconds for execution.
The situation on the database: in a number of mysql tables (everywhere myisam type) there is a lot of data (from 200 thousand to a couple of millions in the table)
Working conditions: The server is combat and not cheap, it is under load. Periodically distorting restarts is extremely difficult and can only be done late at night.
Objective: to optimize work at peak times without interfering with the product code.
Tuning mysql itself gives practically nothing (changes are within the margin of error).
In this regard, a question arose: according to the documentation of the released mysql 5.6, the optimizer (let's say, dirty queries) was seriously redesigned and improved.
On the other hand, there is more than a lot of RAM, and it is quite possible to compare performance not at the peak, and, for example, migrate to another version of MySQL
In this regard, the question arose: how can one server, without stopping the current instance of mysql 5.5, simultaneously raise (install at a different address, and make it listen on a different port), for example, simultaneously mysql 5.6 and mariadb.
For what: I want to duplicate the calculated settings (using tuning-primer.sh) in the same environment to other versions of MySQL, then drive queries from slow-log there, and see how much the speed of their execution changes.
Based on this, it may become clear whether it is possible to at least partially solve the issue of "query quality" (play back the time to find a normal solution to the problem - I don't want to make my version of CMS DLE under high loads) by changing the MySQL version, or switching to MariaDB.

Answer 1

Well, there are ways to get up.
For example here:
www.lissyara.su/__________
or here:
www.mysql.ru/docs/man/Multiple_servers.html
and here:
mrdeff.ru/php/neskolko-kopij-mysql-na-odnom-server...
Respectively it doesn't really matter which version. Install the first one from the packages, as you most likely have it installed.
You collect the second one separately from the sources, changing the paths.
I have not done this myself, but I think after reading you will understand