How Many Applications Can IRun
There is no ‘official’ limit to the number of applications that you can run on your Rails Machine. There is, however, a technical limitation based on how much RAM is available.
Each of your mongrel processes is going to consume between 25-80 MB of RAM. On a base-level Rails Machine VPS with 256 MB of RAM, this means that 3-5 mongrel processes is a reasonable number. So, you can run 3-5 separate apps if you’re willing to only have 1 process per app, or you could run a single application with 3-5 server processes. It all depends on your application’s needs- if you are running RMagick or other memory-hungry libraries, you will not be able to run as many mongrels.
You can check the memory each mongrel is using by running ps aux | grep mongrel_rails and looking at the 6th column of the output.
You can check the current memory usage for the entire system by looking at the buffers/cache line of
free -m