On 12/28/06, Ezra Zygmuntowicz <[EMAIL PROTECTED]> wrote: > > On Dec 28, 2006, at 5:45 PM, Rob Sanheim wrote: > > > Lets say you have a site that is serving, oh, around 100k unique > > visitors a day (plain ole' browser requests) - plus probably ~ 40k > > uniques to feeds. Assume this site is 90% read like most of the web, > > so the traffic looks like your typical news or portal site. There are > > two web boxes behind a hardware load balancer, each doing apache 2.2.3 > > -> mongrel_proxy_balancer -> mongrel clusters. One db machine, but > > that shouldn't be stressed at all due to heavy caching of the content. > > > > Where to being with performance testing something like this? How many > > mongrels per web box to start with? Any comparable sites in > > production to compare it to (Ezra?) > > > > thanks, > > - Rob > > > Hey Rob- > > I am hosting a site that does about 110k unique visitors per day and > about 250k page views/day. I would say it is a typical rails app with > about 85% read and then some write and user contributed uploads and > such. This app is pretty well optimized and doesn't have any requests > except for file uploads that take longer then about 1.5 seconds to > complete with most requests going out at about 35-45req/sec. Pretty > typical rails app. > > It is running on two of our slices which are Xen VM's where there is > a hardware load balancer up front, then nginx proxying to mongrel > cluster on each node. It runs 3 mongrels on each VM for a total of 6. > The database is on another super beefy machine but is not dedicated > entirely to this app and is shared by others. I think this will be a > good place for you to start load testing, 3 - 5 mongrels on each of > your app servers. First get a baseline for your hardware by using ab > or httperf on a fresh rails app that just does render :text => > 'hello' to get the best case scenario for a rails request on your > hardware. This is the fastest you can expect rails to serve a > dynamic request on your boxes. It will probably be around 100-140req/ > sec with sessions turned on. Then do a few more of this same > benchmark against one mongrel and a few of your rails actions that > represent short and long requests for your app. Write these results > down or save them as you go. This is important because I discovered > that 3 mongrels performs *better* then 5 mongrels on our > architecture. This will vary widely though over different os and > hardware configurations. > > Now its time to add more mongrels until you hit a point of > diminishing returns or you are confident in your ability to handle > the traffic you expect plus some. ounds like you have two nice boxes > for your app servers so start with 3 mongrels on one of the servers. > Get this benchmark for the render :text action as well as the other > actions you benched in your real app. At this point you should get > more req/sec when you measure with concurrent users at 20-50. Then > add one mongrel at a time and measure until adding one more mongrel > does not buy you any more performance. This is your sweet spot where > you are maxing out your proxy_balancers efficiency. > > Now that you hit the sweet spot for one app server setup the second > one the same way and do some more benches at high concurrency. If you > have good hardware load balancers you should get a good improvement > with the two app servers over just one of them. In reality software > load balancers don't multiply the perf of a single mongrel by the > number of mongrels. Its more like adding another mongrel may get you > 20-50% more until you hit the sweet spot and can't get anymore. But > the good hardware load balancers are more efficient and get closer to > 50-80% improvement when adding more nodes. Sometimes it's nice to go > straight from the hardware load balancers right to mongrel and use an > asset_host for static content. I don't think you will need this for > the app you are talking about. > > I suspect you will end up with 4-6 mongrels per app server and this > will leave you some overhead for what you need to serve. Another > point of reference is the http://yakimaherald.com gets about 75-90k > page views/day on 3 mongrels behind apache22 on an xserve. > > > > -- Ezra Zygmuntowicz > -- Lead Rails Evangelist > -- [EMAIL PROTECTED] > -- Engine Yard, Serious Rails Hosting > -- (866) 518-YARD (9273)
Ezra, you the man. I'm gonna read this over a few more times when its not 3 am, and I'm sure it will be very helpful with my current project. thanks a lot, Rob _______________________________________________ Mongrel-users mailing list Mongrel-users@rubyforge.org http://rubyforge.org/mailman/listinfo/mongrel-users
