php-cgi constantly recycles every couple of minutes

[merlin corey]

On Thu, Jan 28, 2010 at 8:16 AM, mindfrost82 <nginx-forum at nginx.us> wrote:
> merlin corey Wrote:
> -------------------------------------------------------
>> On Mon, Jan 25, 2010 at 11:17 AM, mindfrost82
>> wrote:
>> > I run a fairly busy site with a Wordpress blog
>> and vBulletin forums.  I recently dumped Apache
>> and and using nginx for everything (which has been
>> incredible and I would never go back).  I'm using
>> PHP as fastCGI and have a wrapper script to start
>> the process.  We average about 1,000 concurrent
>> users at any given time.  Usually anywhere from
>> 800 to 1200+.
>> >
>> > This is the script I found to start php-cgi:
>> >
>> >
>> > #!/bin/sh
>> >
>> > PHP=/usr/bin/php-cgi
>> > PHP_PID=/tmp/php.pid
>> > FCGI_BIND_ADDRESS=127.0.0.1:8888
>> > PHP_FCGI_CHILDREN=4
>> > PHP_FCGI_MAX_REQUESTS=1000
>> >
>> > env -i PHP_FCGI_CHILDREN=$PHP_FCGI_CHILDREN \
>> >
>>  PHP_FCGI_MAX_REQUESTS=$PHP_FCGI_MAX_REQUESTS \
>> >       $PHP -b $FCGI_BIND_ADDRESS &
>> >
>> > echo $! > "$PHP_PID"
>> >
>> >
>> > This has been working great and PHP hasn't
>> completely died on me yet.
>> >
>> > The problem that I'm having is that while
>> viewing TOP, php-cgi seems to die and restart
>> about every 2-3 minutes, sometimes as often as
>> every minute.  At least it restarts itself, but
>> that can take a couple of seconds, causing a delay
>> if you happen to be browsing the site during this
>> time.
>> >
>> > In the above script, I've tried increasing the
>> PHP_FCGI_MAX_REQUESTS, even as high as 1,000,000.
>>  I've also tried completely omitting that value.
>>  No matter what, php-cgi reacts the same way.
>> >
>> > I know it needs to recycle itself to prevent
>> memory leaks, but I don't think it should be
>> happening that often.  Any ideas on how to fix
>> this?
>> >
>> > Posted at Nginx Forum:
>> http://forum.nginx.org/read.php?2,45516,45516#msg-
>> 45516
>> >
>> >
>> > _______________________________________________
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>> > http://nginx.org/mailman/listinfo/nginx
>> >
>>
>> PHP_FCGI_MAX_REQUESTS=1000
>>
>> The children get automatically recycled when using
>> this method, I believe.
>>
>> -- Merlin
>>
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>
> I'm not using php-fpm and don't really want to recompile PHP to switch to it. This is the only issue I have with this setup, so any help is appreciated. I tried taking out the PHP_FCGI_MAX_REQUESTS option altogether and it still recycled itself.  I also upped it to 1,000,000 and it didn't make a difference.
>
> Posted at Nginx Forum: http://forum.nginx.org/read.php?2,45516,46426#msg-46426
>
>
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>

What I was saying was that this is the expected behavior, from what I
can tell.  Even with FPM children will still be getting started, but
you won't ever (in theory) run out of children as can sometimes happen
when php-cgi totally crashes.

You should try tuning for more children, 4 is nothing on such a busy
site.  Try say 16 (or maybe more) children with 4096 max requests and
see if this improves things at all.  If not you'll need to
horizontally scale out to more fastcgi servers for nginx to talk to.

-- Merlin