Krasimir Angelov krasio

This was going to go into a blog post, but was removed after discussion around it being a Bad Thing for customers to do.

Changing the count and memory limit of Passenger processes

To stop applications that are prone to bloating quickly exhausting all the memory on an application instance, we have a script called passenger_monitor that checks for runaway Passenger processes every minute via a cron job. By default, this script is going to look for Passenger workers that are using over 215MB of memory and kill them. Passenger will restart them when needed. We tune the number of workers that run by default on your application instances, based on the memory specifications so that the memory is sensibly utilized. However, if your application legitimately requires more memory than this (i.e. it isn’t bloating) then it may be advantageous for you to reduce the worker count, and allow the lower number of workers to use more memory.

Doing this involves two areas of customization; modifying the Nginx configuratio

Installation

Update your VirtualBox
Download ubuntu LTS server (64 bit)
name “garmz-dev”
Run default installation from the downloaded iso in new VM
- hostname “garmz-dev”
- Don’t encrypt home
- No automatic updates
- Pick OpenSSH server and PostgreSQL server

Installation

Update your VirtualBox
Download ubuntu LTS server (64 bit)
name “garmz-dev”
Run default installation from the downloaded iso in new VM
- hostname “garmz-dev”
- Don’t encrypt home
- No automatic updates
- Pick OpenSSH server and PostgreSQL server

	defmodule HttpRequester do
	use GenServer

	def start_link(_) do
	GenServer.start_link(__MODULE__, nil, [])
	end

	def fetch(server, url) do
	# Don't use cast: http://blog.elixirsips.com/2014/07/16/errata-dont-use-cast-in-a-poolboy-transaction/
	timeout_ms = 10_000

	#!/usr/bin/env ruby

	require 'socket'

	test_file = ARGV[0]

	socket = UNIXSocket.new('testing.sock')

	socket.write(test_file)
	socket.close_write

	- http://www.coffeepowered.net/2009/06/13/fine-tuning-your-garbage-collector/
	- http://snaprails.tumblr.com/post/241746095/rubys-gc-configuration

	article’s settings: ("spec spec" took 17-23!sec)
	export RUBY_HEAP_MIN_SLOTS=1250000
	export RUBY_HEAP_SLOTS_INCREMENT=100000
	export RUBY_HEAP_SLOTS_GROWTH_FACTOR=1
	export RUBY_GC_MALLOC_LIMIT=30000000
	export RUBY_HEAP_FREE_MIN=12500

	$ ruby benchmarks/excon_vs_google.rb

	[em-http-request, HTTParty, Net::HTTP, Net::HTTP (persistent), open-uri, RestClient, StreamlyFFI (persistent), Typhoeus, Excon, Excon (persistent)]

	+--------------------------+-----------+
	\| tach \| total \|
	+--------------------------+-----------+
	\| Excon \| 7.614298 \|
	+--------------------------+-----------+
	\| Typhoeus \| 7.723362 \|

	require 'chronic'

	class PassengerProcess
	attr_accessor :pid, :uptime

	def initialize(passenger_status_line)
	values = passenger_status_line.match(/PID:\s(\d).Uptime:\s(.)$/)
	@pid = values[1].to_i
	@uptime = values[2]
	end