optimization guidelines...

Just Marc marc at corky.net
Wed Jan 14 22:03:29 MSK 2009

Most of the times a load increase on PHP nodes is a direct result of a 
slow db, or certain slow db queries.  Turn on the slow query log on your 
mysql box and eliminate any slow queries you see, especially ones that 
show up often.  Turn on the mysql log which shows sql queries that don't 
use indices and add the appropriate indices.

If you have PHP processes consistently having NOTICEABLE load and you've 
made sure no db queries are slow try http://xdebug.org/  and it will 
give you very useful information - although most of the time this is a 
more advanced method for higher traffic / higher performance sites who 
care deeply about how their scripts behave.

There are countless ways to monitor and keep track of important 
performance metrics on your servers.   Most often it's useful to watch 
more than a few parameters and regularly make sure that the are under 


Olivier Bonvalet wrote:
> Hello,
> if you use a wrapper for PHP with for exemple "export 
> PHP_FCGI_CHILDREN=16", then the opcode cache will be shared between 16 
> php instances.
> If you have 4 or more CPU, you should try to use "xcache" instead of 
> "apc" (and don't forget to adjust the xcache.count parameter), which 
> give much better results for us (about 75% faster in high load).
> Good luck,
> Olivier
> Joe Aston a écrit :
>> I seem to remember using PHP APC with FastCGI was a bad idea because 
>> php-cgi processes couldn't share the same cache - they all required 
>> their own unique caches.
>> How many php-cgi processes are you running?
>> On Wed, Jan 14, 2009 at 4:14 PM, Ilan Berkner <iberkner at gmail.com 
>> <mailto:iberkner at gmail.com>> wrote:
>>     Does anyone have specific or "generic" optimization guidelines for
>>     running Nginx in the following configuraiton?
>>          - Dedicated Nginx server (1)
>>     - PHP FPM
>>     - FastCgi
>>          - Dedicated DB Server
>>     - MySQL
>>          Traffic on our site is increasing and I noticed that CPU
>>     utilization on our Nginx server is going over 50%, primarily to
>>     php-cgi processes.  We are optimizing php using APC.
>>          Any suggestions would be greatly appreciated (additional
>>     information can be provided).
>>          Thanks

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