What is the best way to set up a server for (Rails + PostgreSQL, PostGIS) + (PHP + MySQL) + Mapnik?

Question

PostgreSQL

Hello. Due to the increase in load, an HP DL360 G6 server (Xeon E5504 2.0 GHz, 20 Gb DDR3, SAS 300 Gb 10000 x 4) was purchased.
It is planned to host:
1. Apache + PHP + Passenger
2. Ruby on Rails + PostgreSQL + PostGIS
3. PHP website + MySQL
4. Mapnik + Renderd + TileCache
Previously, all this worked on a regular desktop computer with Intel Core i7, 8Gb DDR3. But after the geography of calculations grew, the CPU load went to 100%. With the installation of all of the above problems will not arise, there is experience.
The question is how best to build the work of the server itself? There is an idea to deploy virtual machines (although there is only experience with Microsoft Hyper-V) separately for a web server, separately for a database, separately for backups. And additionally back up the VMs themselves. In this case, I see many advantages in maintenance, but I don’t know how many resources the management shell will eat and which virtualization system to choose for tasks.
Or install Ubuntu Server and deploy all the listed software in it. Please share your experience in dealing with these issues.

Answer 1

Virtualization in this case seems to me a good solution. You can for example use XenServer
"Shell" will eat quite a bit.
There is a lot of documentation on it and problems should not arise.
Again, with virtualization, it is possible to more accurately distribute the calc. resources between your applications.
Well, do not forget that, for example, a database, in addition to installing it, must also be configured for the appropriate loads. The default settings are evil.
And who "ate" your CPU?