Mongrel vs. Unicorn: A Surprising Benchmark Test Urban Impact

Many designers who’ve been developing with Rails for longer than 3-4 years will keep in mind the Mongrel online Server. Within the very early days of Rails development, Mongrel had been generally speaking considered the method that is preferred of for Rails deployments, if for no other explanation compared to undeniable fact that mod_ruby ended up being painfully slow. Skipping years that are ahead several, we’ve a much wider number of alternatives for deploying Rails based web sites. Such choices consist of slim, traveler, as well as the ever popular Unicorn. With one of these servers, Rails designers are now actually spoiled by having a much simpler implementation procedure. anybody who is knowledgeable about the word “stuck mongrel”, where an internet worker hangs and needs become manually restarted by the operating-system, does know this discomfort.

This week I’d the chance to help a client upgrade one of the legacy systems to a webserver that is new.

Your website had been Mongrel that is using as Ruby handler and we’d noticed an unsatisfactory number of 502 errors. These mistakes took place during durations of high anxiety where in actuality the Mongrel employees had been overloaded and might maybe perhaps maybe not keep pace aided by the need of demands. We first attempted re re solving the difficulty by increasing the amount of employees from 5 to 8. Anyone who’s done this before will probably notice that that is a dual edged blade that may or may well not work. Increasing the wide range of employees will develop how many handlers in your pool, however these employees will eat more RAM and can afterwards slow straight down the system.

After a few times of observing performance, we noted that the rise in employees had a web negative impact, so that it ended up being back again to the drawing board. Just like legacy systems that are most, where in actuality the notion of updating an essential component of a classic system is all about since welcoming as a supper invite from Jeffrey Dahmer, we wasn’t delighted in regards to the concept of ripping out of the old Mongrel webserver. But, having done upgrades that are several Mongrel to traveler into the past, I’ve heard of performance improvements which can be skilled by changing Mongrel.

Thus I put down to see just what form of performance gain i possibly could attain switching from Mongrel to Unicorn. We decided Unicorn due to its rate benefits (forking, UNIX sockets), the feedback that is positive has gotten through the Rails community, and because I like Unicorns (yes, I’ve been known to get a wine on the basis of the label).

My theory was that a change to Unicorn should bring about a lesser normal response times and less 502 Bad Gateway mistakes. The things I discovered kept me personally scratching my mind and re-running performance tests over and over until I became yes I wasn’t crazy.

To try my theory, we penned little a test plan using Apache JMeter that accessed probably the most usually struck pages during my internet application. The vast majority of these pages are look over cached and heavy(although significantly less than i’d like). Then, I went two 30,000 test tests from the web web site, comparing 5 mongrels after which Unicorn employing a UNIX socket.

Here’s just exactly what i discovered screening 50 users that are simultaneous a total of 30k examples per run:

EVERYTHING?? The stark huge difference in standard deviation positively perplexed me. It baffled me personally sufficient that We went the studies 5 more times, but every time We experienced similar outcomes. What exactly is therefore astonishing is the fact that Mongrel, a host understood for stuck employees, done more consistently than its contemporary countertop component. Just just What troubled me personally nonetheless had been that I became not able to duplicate the pesky 502 mistakes experienced within the manufacturing environment. This informs me 1 of 2 things: either my test is certainly not representative of true to life traffic, or my staging host is certainly not affected by the memory that is same imposed with a cycle-sharing hosting provider like Slicehost.

There’s absolutely no nugget that is golden of in this website post except that genuine shock that a mature little bit of technology nevertheless generally seems to endure so well. It is not surprising why slim, another popular internet host, utilizes Mongrel’s parsing engine. We arrived of the knowledge about a higher respect for my old, old buddy Mongrel.