Some tips and troubleshooting ideas for Phusion Passenger

Phusion Passenger manages resources for rails applications – spawning new instances as needed, etc..

• [bash]passenger-status[/bash] – provide the status of passenger rails processes

Configuring Phusion Passenger

Add lines to /etc/apache2/apache2.conf to change the default settings

• [bash]PassengerMaxPoolSize 10[/bash] – maximum number of total rails application instances, the default is 6
• PassengerMaxInstancesPerApp 5 – sets the maximum pool size for any 1 rails application to 10 instances (default is no limit).
• [bash]PassengerUseGlobalQueue ON[/bash] – sets globaly queing on, it is off by default. You want globaly queuing on if your requests have large differences in response times (slow and fast responses).

Related: Passenger documentation

Troubleshooting

If you try [bash]sudo passenger-status[/bash] and get something like
*** ERROR: Cannot query status for Passenger instance 2280:
Connection refused – /tmp/passenger.2280/info/status.socket
Restarting (not reloading) apache [bash]sudo /etc/init.d/apache2 restart[/bash] may fix the problem.