# Nginx Active & Writing Connections exponential growth **URL:** \ **Category:** NGINX\ **Created:** [July 29, 2010, 2:11pm UTC](https://www.ruby-forum.com/t/nginx-active-writing-connections-exponential-growth/192385 "2010-07-29T14:11:26Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![Antonio\_Jerez\_Guill](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/4bbf92/32.png) [@Antonio\_Jerez\_Guill](https://www.ruby-forum.com/u/Antonio_Jerez_Guill)\ **Post date:** [July 29, 2010, 2:11pm UTC](https://www.ruby-forum.com/t/nginx-active-writing-connections-exponential-growth/192385/1 "2010-07-29T14:11:26Z")
Hi there! First of all, I am a new user of the nginx mailing list so there is a short introduction of myself. My name is Antonio, and I have been working for a long time as Web Operations Engineer at [Uptodown.com](http://Uptodown.com), [VisualizeUs.com](http://VisualizeUs.com) and other minor projects. We are running nginx in [Uptodown.com](http://Uptodown.com) for static content, without problems, and in [VisualizeUs.com](http://VisualizeUs.com), since 2 years ago, for static and dynamic content without problems . But it is in visualizeUs where we are having some problems, since we updated nginx to nginx/0.7.67, under debian Lenny 32 bits (aws medium instance), with php-fcgi There is the munin output for nginx connections. [![](http://tinypic.com/images/goodbye.jpg) ](http://tinypic.com/images/goodbye.jpg) We noticed, an exponential growth for connections, better apreciated through the graphic. There is our nginx configuration: [http://dpaste.com/hold/223096/](http://dpaste.com/hold/223096/) And our ulimit for www-data: maxfds …fs.file-max = 200000 core file size (blocks, -c) 0 data seg size (kbytes, -d) unlimited scheduling priority (-e) 20 file size (blocks, -f) unlimited pending signals (-i) unlimited max locked memory (kbytes, -l) unlimited max memory size (kbytes, -m) unlimited open files (-n) 20480 pipe size (512 bytes, -p) 8 POSIX message queues (bytes, -q) unlimited real-time priority (-r) 1 stack size (kbytes, -s) unlimited cpu time (seconds, -t) unlimited max user processes (-u) unlimited virtual memory (kbytes, -v) unlimited file locks (-x) unlimited As active connections grow, response time sligthly increases, so a nginx reboot is needed to get back to optimal response time.Nginx reboots are apreciated in munin graphic when it returns to normal values, in other case, exponential grows continues. We have been tweaking system limits without noticiable diferences. Also we have been working around php-cgi configuration, finding out that the exponential growth of connections still exists but in a slower rate. Anything that make us point in the right direction will be appreciated. Thanks in advanced. Best Regards. Antonio. ---
**Author:** ![Antonio\_Jerez\_Guill](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/4bbf92/32.png) [@Antonio\_Jerez\_Guill](https://www.ruby-forum.com/u/Antonio_Jerez_Guill)\ **Post date:** [July 30, 2010, 11:31pm UTC](https://www.ruby-forum.com/t/nginx-active-writing-connections-exponential-growth/192385/2 "2010-07-30T23:31:15Z")
Hello! On Thu, Jul 29, 2010 at 02:10:23PM +0200, Antonio Jerez Guillén wrote: > (aws medium instance), with php-fcgi > > There is the munin output for nginx connections. > [http://i29.tinypic.com/21y781.png](http://i29.tinypic.com/21y781.png) 1. Are you sure you are measuring connections here? Numbers looks odd, one can’t have 280.57 active connections (which is shown on the first graph as “max”), it should be integer. 2. Are these connections correspond to real client and/or backend connections (i.e. compare with netstat data)? Most likely no, but numbers are suspiciously low. 3. What does nginx -V show? Do you have any third party modules / patches? If yes - are you able to reproduce the problem without them? 4. Are you able to reproduce the problem with 0.8.\*? > We noticed, an exponential growth for connections, better apreciated through > the graphic. Looks like linear one, not exponential, but anyway it looks like socket leak. I don’t remember any socket leaks relevant to 0.7.\* branch which aren’t fixed in 0.7.67. But things changed a lot in 0.8.\* branch and this particular problem may not even appear with new code. > There is our nginx configuration: > > [http://dpaste.com/hold/223096/](http://dpaste.com/hold/223096/) This doesn’t contain full nginx config so it’s mostly useless. […] > As active connections grow, response time sligthly increases, so a nginx > reboot is needed to get back to optimal response time.Nginx reboots are > apreciated in munin graphic when it returns to normal values, in other case, > exponential grows continues. Could you please clarify what do you mean by “slightly increases”? With epoll extra 1k idle connections shouldn’t be noticeable. Maxim D. ---
**Author:** ![Antonio\_Jerez\_Guill](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/a/4bbf92/32.png) [@Antonio\_Jerez\_Guill](https://www.ruby-forum.com/u/Antonio_Jerez_Guill)\ **Post date:** [June 29, 2012, 4:55am UTC](https://www.ruby-forum.com/t/nginx-active-writing-connections-exponential-growth/192385/3 "2012-06-29T04:55:59Z")
Hi, Antonio. I’ve met a very similar situation which you did about 2 years ago. Did you solve this situation? If so, how did you do that? Thanks.