> I would point out that the server load with nginx running with NO CACHING (WP-SuperCache disabled, all queries execute PHP and perform a MySQL query) was something like 1/4 what my Apache/MPM/FastCGI/PHP/WP-SuperCache-enabled setup was using.
This does not compute - no caching (the use of nginx is irrelevant) will always be slower than caching, especially supercache which creates static files for the server to serve directly - even apache can serve those faster than nginx+memcached of the article.
So I would have to say that his caching system under Apache wasn't working.
That would fit the numbers better.
It is true that nginx will perform better than a badly tuned Apache system in the event of a slashdotting but only because it alleviates the slow client problem ie.:
You have 400 concurrent visitors, each one takes up a thread on Apache causing it to saturate, whereas nginx will buffer the request from the client, send it all in one go to the backend, buffer up the response, freeing the backend for another request - an Apache thread would be unavailable for the entire time of that request.
However you can get the same behaviour just reverse proxying from nginx to Apache.
This is all moot though, you can handle even a slashdotting on a 5$/year vps - just make a static version of the page being hit, and serve it directly until the load dies down. 99.9% of requests will be for that page only.
This does not compute - no caching (the use of nginx is irrelevant) will always be slower than caching, especially supercache which creates static files for the server to serve directly - even apache can serve those faster than nginx+memcached of the article.
So I would have to say that his caching system under Apache wasn't working.
That would fit the numbers better.
It is true that nginx will perform better than a badly tuned Apache system in the event of a slashdotting but only because it alleviates the slow client problem ie.:
You have 400 concurrent visitors, each one takes up a thread on Apache causing it to saturate, whereas nginx will buffer the request from the client, send it all in one go to the backend, buffer up the response, freeing the backend for another request - an Apache thread would be unavailable for the entire time of that request.
However you can get the same behaviour just reverse proxying from nginx to Apache.
This is all moot though, you can handle even a slashdotting on a 5$/year vps - just make a static version of the page being hit, and serve it directly until the load dies down. 99.9% of requests will be for that page only.