# Active connections of nginx continually increase

**URL:** <https://www.ruby-forum.com/t/active-connections-of-nginx-continually-increase/220049>\
**Category:** NGINX\
**Created:** [May 25, 2012, 5:59pm UTC](https://www.ruby-forum.com/t/active-connections-of-nginx-continually-increase/220049 "2012-05-25T17:59:03Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![Gurdipe\_D](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/g/b77776/32.png) [@Gurdipe\_D](https://www.ruby-forum.com/u/Gurdipe_D)\
**Post date:** [May 25, 2012, 5:59pm UTC](https://www.ruby-forum.com/t/active-connections-of-nginx-continually-increase/220049/1 "2012-05-25T17:59:03Z")

</div>

I have several nginx web servers as reverse proxy.

I found out that the active connections(including reading writing and  
waiting , seen from http\_stub\_status module) in some of the  
servers(not all of them) are keep growing  
from 3000 to 5000, 10000 … 10k … 50k, and never reduce even in the  
late night.

at the same time , I got a more reliable number from netstat  
netstat -nap | grep 80 | grep EST | wc -l  
2743

the keepalive\_timeout is 10 sec

the worker processes are all started at the same time

```
5265 nginx: master process 6-19:18:55 May19
24498 \_ nginx: worker process 59:34 19:16
24499 \_ nginx: worker process 59:34 19:16
24500 \_ nginx: worker process 59:34 19:16
24501 \_ nginx: worker process 59:34 19:16
24502 \_ nginx: cache manager pr 59:34 19:16

```

I’ve found a similar problem at:

[http://markmail.org/search/?q=Upload+module+%2B+PHP+causes+active+connections+to+continually#query:Upload%20module%20%2B%20PHP%20causes%20active%20connections%20to%20continually+page:1+mid:fdgyk6v32lnvaxul+state:results](http://markmail.org/search/?q=Upload+module+%2B+PHP+causes+active+connections+to+continually#query:Upload%20module%20%2B%20PHP%20causes%20active%20connections%20to%20continually+page:1+mid:fdgyk6v32lnvaxul+state:results)

but seems not the same with me. There’s also no related error in  
error.log

the system is

```
cat /etc/issue
CentOS release 5.3 (Final)
Kernel \r on an \m

uname -a
Linux 2.6.18-128.el5xen #1 SMP Wed Jan 21 11:12:42 EST 2009 x86_64

```

x86\_64 x86\_64 GNU/Linux

the nginx version:

```
nginx -V
nginx version: Nginx/1.0.14
built by gcc 4.1.2 20080704 (Red Hat 4.1.2-44)
TLS SNI support disabled
configure arguments: --prefix=/home/web/nginx/ --user=nobody

```

–group=nobody  
–with- http\_ssl\_module --with-http\_sub\_module  
–with-http\_dav\_module  
–with-http\_flv\_module – with-http\_gzip\_static\_module  
–with-http\_stub\_status\_module  
–http-proxy-temp-path=/home/web/nginx/data/proxy  
–http-fastcgi-temp-path=/home/web/nginx/data/fastcgi  
–http-client-body-temp-path=/home/web/nginx/data/client  
–with-pcre=…/pcre-7.9  
–add-module=…/ngx\_http\_upstream\_keepalive-d7643c291ef0  
–add-module=…/hmux/ --add-module=…/nginx-sticky-module-1.0/  
–with-google\_perftools\_module  
–add-module=…/nginx\_upstream\_check\_module-660183a

the modules are:

```
1: for cookie sticky
nginx-sticky-module.googlecode.com
2: hmux module for resin
code.google.com/p/nginx-hmux-module/
3: upstream check module
github.com/yaoweibin/nginx_upstream_check_module
4: upstream keepalive
mdounin.ru/hg/ngx_http_upstream_keepalive/

```

all patches are applied to nginx src code.

# nginx.conf:

```
user nobody;
worker_processes 4;
worker_cpu_affinity 0001 0010 0100 1000;
google_perftools_profiles /home/web/nginx/tcmalloc/tc;

events {
    worker_connections 51200;
    use epoll;
    epoll_events 4096;
    multi_accept on;
    accept_mutex off; }

http {
    include mime.types;
    default_type application/octet-stream;

    log_format main '$remote_addr - $remote_user [$time_local] '
                  '$status $body_bytes_sent ';

    access_log logs/access.log main;

    sendfile on;
    keepalive_timeout 10;

    server_tokens off;

    gzip on;
    gzip_types text/plain text/css application/x-javascript

```

text/xml application/json application/xml application/xml+rss  
text/javascript;  
gzip\_vary on;

```
    server_names_hash_max_size 4096;
    proxy_buffer_size 64k;
    proxy_buffers 8 64k;
    proxy_busy_buffers_size 64k;
    client_header_buffer_size 64k;
    large_client_header_buffers 4 64k;
    proxy_headers_hash_max_size 1024;
    proxy_headers_hash_bucket_size 128;
    client_max_body_size 25m;

upstream backend{
    check interval=5000 fall=3 rise=2 timeout=2000

```

default\_down=false type=tcp;  
keepalive 1024;  
server server1:80;  
server server2:80;  
}  
server {  
listen 80;  
server\_name xxx;

```
    location / {
         proxy_pass http://backend;
    }

    error_page 500 502 503 504 /50x.html;

    location = /50x.html {
        root html;
    }
}

}

```

Posted at Nginx Forum:

> **[active connections of nginx continually increase](https://forum.nginx.org/read.php?2,226838,226838#msg-226838)**
>
> I have several nginx web servers as reverse proxy. I found out that the active connections(including reading writing and waiting , seen from http\_stub\_status module) in some of the servers(not all of them) are keep growing from 3000 to 5000, 10000...

---

<div class="post-metadata">

**Author:** ![tntzwz](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/8e8cbc/32.png) [@tntzwz](https://www.ruby-forum.com/u/tntzwz)\
**Post date:** [May 25, 2012, 6:14pm UTC](https://www.ruby-forum.com/t/active-connections-of-nginx-continually-increase/220049/2 "2012-05-25T18:14:32Z")

</div>

> from 3000 to 5000, 10000 … 10k … 50k, and never reduce even in the late  
> night.

Just to be sure - are you not by any chance reading the all time total  
values (3rd line) instead of the actual ones which are on  
4th?  
e.g. can you show what’s your ‘stub\_status on’; location output actually  
looks like?

rr

---

<div class="post-metadata">

**Author:** ![tntzwz](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/8e8cbc/32.png) [@tntzwz](https://www.ruby-forum.com/u/tntzwz)\
**Post date:** [May 26, 2012, 4:05am UTC](https://www.ruby-forum.com/t/active-connections-of-nginx-continually-increase/220049/3 "2012-05-26T04:05:36Z")

</div>

## Reinis R. Wrote:

> > from 3000 to 5000, 10000 … 10k … 50k, and  
> > never reduce even in the late night.
> 
> Just to be sure - are you not by any chance  
> reading the all time total values (3rd line)  
> instead of the actual ones which are on  
> 4th?  
> e.g. can you show what’s your ‘stub\_status on’;  
> location output actually looks like?

thanks for your remind. I’m for sure to record the 1st line and 4th  
line of the status output

curl [http://server1/status](http://server1/status)  
Active connections: 40265  
server accepts handled requests  
16856987 16856987 28380346  
Reading: 2583 Writing: 267 Waiting: 37415

and on the web server at the same time:  
netstat -nap | grep EST | grep 80 | wc -l  
3818

I recorded the numbers using the following scripts, it has been tested.

RAWdata=`curl http://${Host}/status 2>/dev/null`  
ToNagios=`echo $RAWdata | awk '{ if ($3 > '$Active_Num_WARNING' || $12 > '$Read_Num_WARNING' || $14 > '$Write_Num_WARNING' || $16 > '$Wait_Num_WARNING' ) printf( "'$Host'" " Warning |Active_connections_are="$3 ";;;; Reading="$12 ";;;; Writing="$14 ";;;; Waiting="$16 ";;;;") else printf( "'$Host'" " OK |Active_connections_are="$3 ";;;; Reading="$12 ";;;; Writing="$14 ";;;; Waiting="$16 ";;;;") }'`

sample output:  
[xxx@desktop ~]$ RAWdata=`curl http://server1/status 2>/dev/null`  
[xxx@desktop ~]$ echo $RAWdata  
Active connections: 44476 server accepts handled requests 17371377  
17371377 29208687 Reading: 2839 Writing: 312 Waiting: 41325

from the diagram recorded, you can see not only waiting but also reading  
, writing are all increasing

> rr
> 
> * * *
> 
> nginx mailing list  
> [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
> [mailman.nginx.org archive](http://mailman.nginx.org/mailman/listinfo/nginx)

Posted at Nginx Forum:  
[http://forum.nginx.org/read.php?2,226838,226845#msg-226845](http://forum.nginx.org/read.php?2,226838,226845#msg-226845)

---

<div class="post-metadata">

**Author:** ![tntzwz](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/8e8cbc/32.png) [@tntzwz](https://www.ruby-forum.com/u/tntzwz)\
**Post date:** [May 27, 2012, 7:19pm UTC](https://www.ruby-forum.com/t/active-connections-of-nginx-continually-increase/220049/4 "2012-05-27T19:19:43Z")

</div>

Hello!

On Fri, May 25, 2012 at 11:58:22AM -0400, tntzwz wrote:

> ```
> 2743
> 
> ```

[…]

> –http-proxy-temp-path=/home/web/nginx/data/proxy  
> –http-fastcgi-temp-path=/home/web/nginx/data/fastcgi  
> –http-client-body-temp-path=/home/web/nginx/data/client  
> –with-pcre=../pcre-7.9  
> –add-module=../ngx\_http\_upstream\_keepalive-d7643c291ef0  
> –add-module=../hmux/ --add-module=../nginx-sticky-module-1.0/  
> –with-google\_perftools\_module  
> –add-module=../nginx\_upstream\_check\_module-660183a

Obvious suggestion is: try compiling nginx without any third party  
modules and patches.

Maxim D.

---

<div class="post-metadata">

**Author:** ![tntzwz](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/t/8e8cbc/32.png) [@tntzwz](https://www.ruby-forum.com/u/tntzwz)\
**Post date:** [May 28, 2012, 6:11am UTC](https://www.ruby-forum.com/t/active-connections-of-nginx-continually-increase/220049/5 "2012-05-28T06:11:56Z")

</div>

> Obvious suggestion is: try compiling nginx without  
> any third party  
> modules and patches.

thanks, I’ll try this

> Maxim D.
> 
> * * *
> 
> nginx mailing list  
> [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
> [mailman.nginx.org archive](http://mailman.nginx.org/mailman/listinfo/nginx)

Posted at Nginx Forum:  
[http://forum.nginx.org/read.php?2,226838,226889#msg-226889](http://forum.nginx.org/read.php?2,226838,226889#msg-226889)