php-fpm tuning

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Sudheer M

May 17, 2019, 1:02:44 PM5/17/19
to highload-php-en
 I have 2 web servers with 16GB RAM and 8 Core CPU each. where as Database Server separate with 32 GB RAM and 8 Core CPU.

Below is the average used for php-fpm

pgrep -f php-fpm | xargs -r ps --no-headers -o "rss,cmd" | awk '{ sum+=$1 } END

{ printf ("%d%s\n", sum/NR/1024,"M") }'


--> Am using below configurations method to tuneup php-fpm service

pm = dynamic

pm.max_children (total RAM - (DB etc) / process size)

pm.start_servers (cpu cores * 4)

pm.min_spare_servers (cpu cores * 2)

pm.max_spare_servers (cpu cores * 4)

pm.max_requests 1000

Below is the error am getting in php logs

WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers)

And Nginx error as below

connect() to unix:/var/run/php/php7.2-fpm.sock failed (11: Resource temporarily unavailable) while connecting to upstream, client:

Could you please help me in setting up php parameters and resolving this issue.

Nikola Filipović

May 17, 2019, 7:14:50 PM5/17/19

Might be your MySQL server not being able to respond quickly to all the queries, I’ve seen that happen too.

Also, considering the resources you have available, I think you might be better off setting the process manager to static which will allocate all the resources on startup. Here are a couple of articles that helped me when I was configuring a PHP-FPM stack for high load. 


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Sudheer M

May 19, 2019, 10:56:05 AM5/19/19

Hello Nikola,


Thanks a lot for your response. As you mentioned “Mysql Server not being able to respond quickly” could you please suggest where should I check this because I don’t see any mysql error logs in the server.



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Sudheer M

Sr. DevOps Engineer

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