I have a Debian Linux VPS server for my production website (512MB).
I'm using Phusion Passenger with Apache to service my Rails 2.3.4 application with Ruby 1.9. I'm limiting the pool of Phusion passenger instances to 3
Although the traffic is relatively low, the server crashes at times and I notice (when using 'top' command) that there are many instances of apache (/usr/sbin/apache2 -k start) maybe like 20 of them taking up all the memory I have and the website become un-responsive.
I'm not sure what to do about this, where to start digging for potential issues or how to spot or limit the number of apache instances.