However, once you’ve launched your application and people start actually using it, you may find server experiencing excessive swapping once the traffic begins to pick up. Before getting too deep into scaling, caching, upgrading your server, etc., there are a few Passenger settings you can tune to wring out the best performance your existing stack. I’ll address these settings with a few rules of thumb we’ve gathered from the Passenger documentation and simple trial-and-error.

Before getting started, we highly recommend employing Munin (instructions for Munin with Passenger here) and NewRelic Performance Monitoring for your Passenger/Rails application, so that you can fine-tune your settings for the best performance.

Note: the following settings are specific for Apache, you will need to modify the syntax/file-names for Nginx.

Per-server Settings

These settings are set per-server, meaning if you have multiple applications running on the server, these should be set only once throughout all of your .conf files. If you have only one Rails/Passenger app on the server, then you may set these in that application’s .conf file. On Ubuntu, this may be found at /etc/apache2/sites-available/yourapp.conf.

A more appropriate place for these however would be in Apache’s .conf file.

PassengerMaxPoolSize and PassengerPoolIdleTime

/etc/apache2/apache2.conf:

You can essentially copy and paste this into your apache conf file. I’ve added some notes in there to help you remember how they should be tuned.

PassengerMaxPoolSize: This is the number of Passenger instances that can be spawned at once for your site. This basically relates directly to the amount of RAM that is available to your application. However, it is not a linear relationship. It’s more of an exponential relationship. Numbers that we and others have found to work well are:

Since this depends on available RAM, this will vary depending on what other processes are running on your server, such as MySQL, etc. If you have Munin installed with the Passenger plugins, you can monitor the Passenger Memory Stats and Passenger Status graphs to tweak this as necessary.

PassengerPoolIdleTime: This is essentially the amount of time (in seconds) that each Passenger instance continues to run after it becomes idle (i.e. someone stops clicking around the site). According to the documentation, this should be set to the average time a visitor views a page multiplied by 2. This of course prevents Passenger instances from shutting down (and thus having to re-spawn) while someone is viewing a page.

If your application has been in production long enough to have a few hundred viewers and you have Google Analytics installed, an easy way to get the ideal setting for your application is to take the Average Time on Site, divide by the Average Page Views per Visit, and multiply by 2.

PassengerMaxInstancesPerApp (optional)

If you do have more than one Rails/Passenger application on the server, you may optionally set PassengerMaxInstancesPerApp.

PassengerMaxInstancesPerApp: This is the maximum number of instances each application may use of the total PassengerMaxPoolSize. Therefore, PassengerMaxInstancesPerApp must be smaller than PassengerMaxPoolSize.

For example, if you have 2 applications running on one 256MB server, you may want to set PassengerMaxInstancesPerApp to 1, so that one app may never hog all of the rails instances at the expense of the other app. If you have 2 applications running on a 512MB server (PassengerMaxPoolSize 6), then you may want to set cci]PassengerMaxInstancesPerApp[/cci] to 4 or 5 to allow each app to better handle higher load (hopefully while the other app is under less load).

RailsAutoDetect

To get a little more performance out of your server, you can also turn the RailsAutoDetect setting of Passenger off. This will make it so that each request through Apache does not check to see if it is a Rails request that requires Passenger. However, this will now require that you explicitly tell Apache which requests are Rails and do require Passenger, using RailsBaseURI. This is easy though.

Again, in your apache2.conf file:

Now, within your the Vhost block in your site’s .conf file, you will need to set the RailsBaseURI:

Here is a complete example of the Passenger block in your apache2.conf file:

And a simple sites-available/yourapp.conf may look like this:

More Passenger Configuration Settings

These settings so far only scratch the surface of Passenger configuration. Give the Passenger documentation a good read-through for more information on configuring Passenger.

Further Reading: Apache Settings

At this point, if you still need to squeeze more performance out of your server (and you will eventually), you’ll want to configure Apache to utilize its resources most efficiently with Passenger. I recommend reading through this thread on the Slicehost forums to get a good idea just how much trial-and-error this will take. Keep a close eye on your server when you tweak these settings, you may end up making it slower several times before finding that sweet spot.

You may read the documentation for each setting in the Apache docs (note that these are the Apache 1.3 docs, but they still explain purpose of each setting well). For more information using these settings to reduce the RAM consumed by Apache, see this other Slicehost forum and this blog post on saving RAM with Rails and Passenger.

If you’re impatient and just want to get something better than default, here are some numbers that worked well for us on a recent application running on a 256MB VPS on Slicehost. These settings can be found in your apache2.conf file.

Why this doesn’t work: You proceed with creating a custom theme for your Wordpress blog that looks exactly like your Rails application. Then over the next couple years, you begin to realize how tedious this solution is. You have to copy over your CSS stylesheets from your Rails app, your Javascript files (if your standard layout contains any Javascript elements, like a Twitter widget in the footer or whatever), and your layout images and assets. Then, every time you change or update the layout of your Rails app, you have to copy the changes in your custom Wordpress theme. And you cannot just copy the changes, because if you have any Ruby/Rails functionality in the layout, you have to translate them into PHP functionality in your Wordpress layouts.

And then there’s the impossible stuff… if anything in your Rails app layout loads information from the database in your Rails app, then you cannot have those elements in your Wordpress layout, unless you do something like create an XML or JSON feed in your Rails app and then import it in your Wordpress layout. But this is quite tedious still if you want to change any of it!

There’s an easier way.

Include Your Rails Layout Directly In Your Wordpress Layout

The solution I found turns out to be quite simple. The basic idea is to create a :partial in your Rails app layout, make it publicly accessible via your config/routes.rb, have it generate and simply return the appropriate html using your controller method, and then import that html (and CSS) in your Wordpress layout.

For this to really work well, you’ll want to make sure that you make your Rails app cache the partials to be imported into your Wordpress layout, so that a lot of traffic on your blog doesn’t cause your Rails app server to explode.

1. Break Your Rails Layout into Partials

The first step is to break as much of your app/views/layouts/application.html.erb into partials as possible/desired. At the very least, this means a header and a footer partial. Typically, you would not include the stuff in the <head> part of the layout, because your Wordpress will likely require additional stylesheets and a different set of javascripts (not to mention you’ll want to make your meta information specific for your blog pages).

A simple Rails layout using this method would look something like this:

I’ve also included a widgets partial to show that this can be done with static javascript widgets as well.

Note that your layout and partials can have any and all Ruby/Rails code in them that you want. Since your Wordpress theme is importing this stuff from your Rails application, the Rails app will run as usual and just return the end result, which is HTML, so your Wordpress will have no problem interpreting it.

A simple app/views/static/_header.html.erb partial may look something like this:

Notice that the normal links in the header are “active” simply if the current URL matches the link path, but the “Blog” link is active if the @blog variable is set and true. This is because, as you will see in the next section, the URL for the header when it is called from your blog won’t be the blog URL.

2. Make Your Layout Partials Publicly Accessible

The next step is to make your layout partials publicly accessible. I.e. make it so that you can access your layout partials from the browser using a direct URL, like http://mysite.com/static/header. The actual URL you use doesn’t really matter, because users won’t ever need to see or use it.

The way we do this is to explicitly set a path for each layout partial in our config/routes.rb and then create a controller method for each that renders the HTML generated by the partial.

A path in your routes for your header partial might look like this:

Then in the app/controllers/static_controller.rb, your corresponding action would look like this:

Now, hopefully you see why, in the header partial, we couldn’t just say that the blog menu item is :class => ('active' if request.path == blog_path). The path that the header partial will be seeing when the Wordpress layout requests it will be the path you defined in your routes.rb, in this case "static/header". This is why we instead say :class => ('active' if @blog) and then set @blog = true in the controller action.

Include the Rails Partials In the Wordpress Layout

Here’s the real trick. In order to include the Rails partials in your Wordpress layout, you might be inclined to use on of these PHP functions: include() or require(). This won’t work though for two reasons.

1) include() and require() both read .php files. However, your publicly-accessible layout partials are going to return straight HTML.

2) By default, neither method allows absolute URLs due to security precautions. You can change your PHP setup to allow this, but again, this is a security issue. Not to mention, for our purposes, you still would have to deal with reason 1 above.

Instead, we can use PHP’s function to retreive HTML code, file_get_contents().

In your wp-content/themes/my_theme/header.php file, you would then include this line:

Import the Rails CSS Stylesheet for Wordpress

Of course, you’ll also want to import the base stylesheet that styles your layout HTML for your Wordpress theme. You can do this a few different ways. The easiest is to just include it in your header.php file in the <head> area like any other stylesheet, just using the absolute URL to the CSS file.

Notice that we include the Rails app stylesheet before the blog stylesheet. This is so that it’s easy to override any of the styles we need to specifically in the blog stylesheet.

An alternative way we can do this is using the CSS @import method.

Cache the Layout Partials On Your Rails Server

The astute programmer in you may have noticed by now that this turns a single request on your blog into multiple additional requests on your Rails app server (one additional request per partial that’s imported in your Wordpress layout, e.g. header, footer, etc.). We can’t have that!

Luckily this is easy to fix with Rails’s built-in page-caching.

In your app/controllers/static_controller.rb file, include the following.

And make sure that caching is turned on in your production app, in config/environments/production.rb:

And/Or Cache Your Wordpress Pages (recommended)

Of course, if you install and setup caching in your Wordpress installation (highly recommended), then the complete layout files will be cached and never even need to make calls to your Rails application after the cached pages are generated the first time. This is even faster for your Wordpress blog, because it’ll load faster now that it doesn’t have to import portions of the layout from an external URL every time a page is loaded.

Note that when you do this, you’ll need to expire/delete the cached Wordpress files anytime you update the layout in your Rails app.

Done!

Now you have a great looking Wordpress blog that looks like you’re never leaving your Rails application. And best of all, you don’t have to tediously duplicate efforts every time you update your Rails app layout! How’s that for DRY design?

Munin is a great tool to monitor resources on your server, showing graphs over time, so that you can analyze resource trends to find what’s killing your server before it causes major problems. It is also very configurable and can be made to profile and graph just about anything via plugins. And with a couple tricks, you can get it to monitor your Phusion Passenger application with ease.

If you already have Munin installed and working, and just want to know how to get the Passenger Plugins working, you can skip directly to Install Munin Passenger Plugins, Configure Munin for Passenger Stats, and be sure to read the Gotcha.

Install Munin and Munin-node

The first step is to install Munin. If you have your server running Ubuntu, this is pretty easy. One you’ve SSH’d into your server, enter:

If you’re running another flavor of Linux, see the Munin’s Linux install instructions. For Mac OSX, see Mac install instructions.

Install Munin Passenger Plugins

The next step is to install the Passenger plugins. The first is passenger_status:

The second plugin is passenger_memory_stats:

No go ahead and restart Munin-node (this is the process that runs Munin at regular intervals):

Configure Munin

Now here are where those couple of tricks come in to get Munin playing nicely with your Rails application. First we want to tell Munin where to store the html and graph images that you can access through the browser.

And change the following lines:

Note that the htmldir can really be any directory, but make sure it’s persistent (i.e. if you’re using Capistrano to keep revisions of your app on the server, make sure the munin directory is in the shared directory outside of your rails app root directory).

Also note that the [yoursite.com] part is only a descriptive name, so it really doesn’t matter what you call it. If you have a more complex application that runs from multiple directories or multiple servers, you can group Munin stats, and in this case, you actually have to put some thought into this line. But that’s outside the scope of this article, so you can read up on customizing Munin Master on your own time if you’d like.

Now if you haven’t already, you need to actually create that directory you just told Munin about:

Configure Munin For Passenger Stats

And finally, you need to allow the munin user to run the passenger-status and passenger-memory-stats commands without a password, since they both require sudo powers to run properly.

And at the bottom of the file add:

Gotcha

At this point, Munin is suppose to start doing it’s stuff and all is happy in the ruby-munin marriage. For me, however, this was not the case. After combing the Munin error logs and digging through the Munin documentation and code more than I care to admit, I realized that Munin-node needs to preface the passenger stat commands with ruby. So, here’s how we fix that:

And then add this to the bottom of that file:

Final Munin Restart

Now we’ll give Munin-node one more restart and we’re in business.

After waiting a few minutes, you should start to see .html files and graphs and whatnot in the /path/to/your/rails/shared/directory/munin directory. If not, you want to check out the Munin-node error logs to see what’s going on. On Ubuntu, this is found at /var/log/munin/munin-node.log.

View Munin From Your Browser

So now, Munin is running, but what good is it if you can’t view the pretty output? Typically the best way to do this is through a sub-domain. If you have yoursite.com, let’s set up Munin to be viewable from munin.yoursite.com. All you need to do is point to the /path/to/your/rails/shared/directory/munin directory for munin.yoursite.com in your site’s server conf file. For example, if you’re on Apache, you’d just do this in your sites-available/yoursite.conf

And make sure you have the proper A-name record setup for munin.yoursite.com with your NameServers.

Once domain propogation magic happens, you should now be able to see this when you navigate to munin.yoursite.com

Munin main page

The Passenger stats will be in the “App” section.

Have fun now monitoring your Passenger Rails application with passenger usage trending. Remember to use your newfound power for good.

(irqstats patch)

If you find that the irqstats graph doesn’t work, you may need to patch the irqstats plugin. Basically you just need to sudo nano /etc/munin/plugins/irqstats and change

to

*the post below was originally written Dec 9, 2009, while this screenshot was captured on Dec 30, when the post was *published, which explains the slight discrepency... I didn't feel like going back and rewriting it

The Point

The other day, I went to search for something on Google and noticed some interesting results from Google’s suggest feature after typing just one letter. Wow, I thought. How presumptuous of Google to think it can guess my will and desires from one letter. Of course that then led to curiosity, and hence this post. What terms manage to garner the top 10 spots for each letter of the English alphabet? So without further ado, the top 10 terms for each letter on Google’s suggest feature (along with some of my comments).

Interesting Statistics

Brand names: 195 (75%)

Generic Search Terms: 44 (16.9%)

TV Shows / Movies: 6 (2.3%)

Famous People / Bands: 9 (3.5%)

Search Engines: 6 (2.3%)

amazon

aol

american airlines

addicting games

ask.com
*interesting that one of the top results in the Google search engine is another search engine

at&t
*people actually type the ampersand into the search box

at&t wireless

autotrader

apple
*Apple makes it difficult for people who want to find information about fruit

american airlines

b

bank of america

best buy

bed bath and beyond

bank of america online banking

barnes and noble

bing
*another search engine

blockbuster

baby names
*notice that the vast majority of suggested terms are brand names… this is not

burlington coat factory

borders

c

craigslist

cnn

comcast.net

costco

chase

club penguin

capital one

comcast

continental airlines

cartoon network

d

dictionary.com

dictionary
*function people can search… like dictionary “idiosyncratic” where google has a dictionary function

disney channel

delta airlines

direct tv

dell

dillards

dominos
*another example of a proper noun making it difficult to search for a common noun… seriously, I want to know more about how to play

dancing with the stars
*this is one popular show

daylight savings 2009

e

ebay

espn

expedia

ebay.com

express

ebay motors

english to spanish translation

evite

enterprise

erin andrews

f

facebook

facebook login

fox news

food network

firefox

fandango

forever 21

fedex

free online games

fedex tracking

g

gmail

google maps

google earth

google.com
*damn kids trying to break the internet!

games

gamestop

glee

google translate

google wave

geico

h

hotmail

hulu

home depot

halloween costumes

h1n1 symptoms

hollister

horoscope

hobby lobby

hotels.com

hp

i

imdb

ikea

itunes

inspirational quotes

itunes download

irs

iphone

ikea usa

isohunt

inglorious bastards

j

jet blue

jcpenney

justin tv

joann fabrics

justin bieber

jobs

jokes

java

jimmy johns

jcrew

k

kohls

kelly blue book

kmart

kayak

kinkos

kings of leon

kroger

kanye west

kim kardashian

kaiser permanente

l

lowes

lyrics

limewire

lady gaga

love quotes

linkedin

lands end

louis vuitton

ll bean lego

m

myspace

mapquest

msn

maps
*yeah this could conceivably be counted as a brand name (someone on Google searching for maps is probably looking for Google maps), but we’re going to give it the benefit of the doubt as a generic term

mapquest driving directions

macys

mega millions

mortgage calculator

myspace layouts

miniclip

n

netflix

nfl.com

new york times

nordstrom

northwest airlines

nbc

nickelodeon

new moon

nick jr

news

o

office depot

old navy

orbitz

overstock

office max

oprah

online games

olive garden

owl city

open office

p

pandora

party city

photobucket

pizza hut
*who takes the top spot for the coveted pizza spot for “p”

papa johns

paypal

poptropica

powerball

pirate bay

people of walmart

q

quotes
*people love quotes

qvc

quotes about life

quest diagnostics

quicktime

quiznos

quotes about love

qwest

quizzes

quotes and sayings

r

realtor.com

reverse phone lookup

radio shack

redbox

runescape

recipes

rei

restoration hardware

rotten tomatoes

rate my professor

s

southwest airlines

swine flu symptoms

sears

spanish translation

skype

staples

sprint

sams club

sports authority

sparknotes

t

target

twitter

thesaurus

travelocity

translator

ticketmaster

tmobile

tv guide

tmz

toys r us

u

usps

ups

united airlines

ups tracking

us airways

urban dictionary

ufc

urban outfitters

usaa

us bank

v

verizon wireless

verizon

victoria secret

vampire diaries

vlc

virgin america

vh1

verizon.net

virgin mobile

value city furniture

w

walmart

weather

white pages

wikipedia

www.facebook.com

web md

www.yahoo.com

webkinz

wells fargo

walgreens

x

xbox 360

xm radio

xbox live

xkcd

xanax

xcel energy

xm radio online

xbox 360 games

xbox 720

xbmc

y

youtube

yahoo

yahoo mail

yellow pages

yahoo.com mail

yahoo answers

yahoo maps

youtube music

yahoo finance

yahoo fantasy football

z

zillow

zappos

zip codes

zip codes by city

zombieland

zodiac signs

zune

zune hd

zero punctuation

zabasearch

Nanoc

Nanoc’s website describes it as “a tool that runs on your local computer and ‘compiles’ documents written in HTML, Markdown, Textile, Haml, etc. into a static web site, ready for uploading to any web server.” Basically, it takes your dynamic Ruby code and turns it into static HTML which you can then upload to your server, meaning you don’t necessarily need Ruby installed on your server. Of course, this depends on what your site actually needs to do. But I could see this as a perfect fit for a Blog, for which you write posts on your local machine and deploy. Of course you’d need to implement comments with a third-party javascript widget like Disqus, but that’s just one example.

Mongoid

Mongoid is a Ruby ODM framework for mapping your Ruby application to use MongoDB for object storage. If you haven’t checked out MongoDB as an alternative to using MySQL for your storage needs, it’s worth a look. You may not even realize you have different needs until you discover there’s a database out there to fit those needs. For another cool Database-Ruby integration alternative, see Friendly, a gem that makes MySQL look like a document-store to your application.

RAD

RAD stands for Ruby Arduino Development, and it is a library that allows you to write Arduino programs in Ruby. If you haven’t checked it out, Arduino is an open-source electronics prototyping platform. You can do lots of cool stuff with it. And with RAD, if you’re a Ruby developer, it’s now easier than ever to get started.

Racksh

Racksh is a console for any Ruby-based application. According to the site, “It’s like Rails’ script/console or Merb’s merb -i, but for any app built on Rack. You can use it to load application environment for Rails, Merb, Sinatra, Camping, Ramaze or your own framework provided there is config.ru file in app’s root directory.” So if you’re building Ruby stuff and hate having to go to your browser (or compiling as the case may be) to test out functionality, this should make your life a whole lot easier.

Miso

Miso is a unified API for simple image manipulation, such as cropping and resizing. It gives your code a common API that plugs into image software libraries like Core Image for Macs and ImageMagick. No more worrying about the specificity of your environment when manipulating images in your application.

Ruby Version Manager

RVM allows you to install and use multiple versions of Ruby on your machine. RVM came highly recommended from a friend, and it sure delivers. Now you can upgrade without the irreversibility of times past. Great for those of us who have a hard time with commitment

Others

Do you have any other cool Ruby projects you think should have been included? Let me know! Maybe we can make this post an awesome new series.

I recently stumbled upon an article called, “If You’re Nervous About Quitting Your Boring Job, Don’t Do It”

As you can tell by the title of my post, I disagree. Let’s put aside the fact that I would not come to the conclusion that Lisa (the case study for the above post) should not have quit her job based purely on the fact that she failed the first time out. That’s completely normal, and I’d be excited to see what Lisa learned and how she applies it to her next endeavor. No, even more than that, I disagree with sentiment of the post.

Who knows what the future will bring, but I think I fall into the category of people “who have built up rare and highly desirable skills” and have accomplished a lot since I left my full-time engineering job to pursue my entrepreneurial passions.

My point here isn’t to brag, but simply to say that when I decided to pursue my passion and the desireable lifestyle of entrepreneurship, quitting my full-time job was one of the most nerve-racking and toughest decisions I’ve ever made, full of doubt and second-guessing. If you are having doubts or second thoughts about quitting your job, then congratulations, you are a pragmatic, rational, sane human-being.

That said, I did a lot of option-weighing and analysis of my situation, and I don’t think quitting your job is for everyone. I didn’t have a family to support, I already bought a car and had a place to live (topic for another post: “what entrepreneurship does to your credit”), and I had a business that was on the verge of profitability at the time I quit. I would not advise anyone to quit without seriously thinking this decision through. In fact, if at all possible, check out these alternatives to quitting your job outright to start your own company.

I’m not trying to pick on the guys over at Study Hacks, but I think that it is very easy to say, “if I wanted to start my own company (which I don’t), I wouldn’t feel nervous,” when you have no real intention of quitting your job or starting your own company.

For instance, I can tell you that if I won the lottery, I would give all of the money to charity, because I don’t need it and I wouldn’t want it to come between me and my friends or family. Also, if I were ever confronted by a gun-wielding Agent Smith, I would calmly flex my space-time muscles, look square in his bright-green, scrolling-character soul, and extract the light from inside of his bursting flesh. And I can make both claims with equal sincerity, because I have no expectations or intentions of either ever happening.

My point is, don’t quit your job because I tell you to. And don’t not quit your job because he tells you not to. Just remember, the only certain path to failure is to not try.