Frederico Araujo fred

Zero downtime during upgrades and scaling out system (such as zero seconds downtime, while app still runs)
Highly Scalable with Terabytes of data with high performance and low cost with shards
Automatic Replica Set member take-over in case of failing primary, with automatic recovery for returning hosts.
Automatic promotion to primary and de promotion for any member of a replica set based on performance and latency.
Journaling, allows safe recovery in case of hard-disk failure.
Strong consistency, "Afford to loose data" in mongoDB is myth. Data is not lost, it's only not persisted due to failures on the developers code.
When Sharding is not feasible, different Documents (rails models) can be on different Replica sets (different database or set) altogether, since there are no joins in Mongo.
Background indexes.

Credit Card Regex

Amex Card: ^3[47][0-9]{13}$
BCGlobal: ^(6541|6556)[0-9]{12}$
Carte Blanche Card: ^389[0-9]{11}$
Diners Club Card: ^3(?:0[0-5]|[68][0-9])[0-9]{11}$
Discover Card: ^65[4-9][0-9]{13}|64[4-9][0-9]{13}|6011[0-9]{12}|(622(?:12[6-9]|1[3-9][0-9]|[2-8][0-9][0-9]|9[01][0-9]|92[0-5])[0-9]{10})$
Insta Payment Card: ^63[7-9][0-9]{13}$
JCB Card: ^(?:2131|1800|35\d{3})\d{11}$
KoreanLocalCard: ^9[0-9]{15}$

	# First configure your models to use Amazon s3 as storage option and setup the associated S3 config.
	# Then add the classes your want to migrate in the klasses array below.
	# Then run rake paperclip_migration:migrate_to_s3
	# Should work but this is untested and may need some tweaking - but it did the job for me.

	namespace :paperclip_migration do
	desc "migrate files from filesystem to s3"
	task :migrate_to_s3 => :environment do
	klasses = [:model_1, :model_2] # Replace with your real model names. If anyone wants to this could be picked up from args or from configuration.
	klasses.each do \|klass_key\|

	# app/models/post.rb

	class Post

	searchable :auto_index => false, :auto_remove => false do
	text :title
	text :body
	end

	after_commit :resque_solr_update

	#app/controllers/application_controller.rb
	class ApplicationController < ActionController::Base
	def opensearch
	response.headers['Content-Type'] = 'application/opensearchdescription+xml; charset=utf-8'
	end

	## mysql::master
	ruby_block "store_mysql_master_status" do
	block do
	node.set[:mysql][:master] = true
	m = Mysql.new("localhost", "root", node[:mysql][:server_root_password])
	m.query("show master status") do \|row\|
	row.each_hash do \|h\|
	node.set[:mysql][:master_file] = h['File']
	node.set[:mysql][:master_position] = h['Position']
	end

	namespace :workers do
	namespace :clockwork do
	desc "Stop clockwork"
	task :stop do
	on roles(:app) do
	within release_path do
	with rails_env: fetch(:rails_env) do
	execute :bundle, :exec, :clockworkd, "-c lib/clockwork.rb --pid-dir=#{cw_pid_dir} --log-dir=#{cw_log_dir} stop"
	end
	end

	_bundler_complete()
	{
	if [[ ! `which bundle` ]]; then
	return
	fi

	local cur prev commands
	commands="help install update package exec config check list show outdated console open viz init gem platform"
	cur="${COMP_WORDS[COMP_CWORD]}"
	prev="${COMP_WORDS[COMP_CWORD-1]}"