# Mongrel errors overload Nginx's error.log and server's CPU

**URL:** <https://www.ruby-forum.com/t/mongrel-errors-overload-nginxs-error-log-and-servers-cpu/146079>\
**Category:** Deployment\
**Created:** [August 17, 2008, 2:48pm UTC](https://www.ruby-forum.com/t/mongrel-errors-overload-nginxs-error-log-and-servers-cpu/146079 "2008-08-17T14:48:01Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![stanislav](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/s/e5b9ba/32.png) [@stanislav](https://www.ruby-forum.com/u/stanislav)\
**Post date:** [August 17, 2008, 2:48pm UTC](https://www.ruby-forum.com/t/mongrel-errors-overload-nginxs-error-log-and-servers-cpu/146079/1 "2008-08-17T14:48:01Z")

</div>

Hello,

I’m considering to replace our production server Apache with Enginx.  
Behind them there are a dozen of mongrel\_rails instances. Some of the  
features that I like very much in Nginx are - fair load balancing for  
proxy upstreams and the posibility to define servers as backup.

## This is my current configuration:

http {  
include /etc/nginx/mime.types;  
default\_type application/octet-stream;

```
log_format main '$remote_addr - $remote_user [$time_local]

```

$request ’  
'“$status” $body\_bytes\_sent “$http\_referer” ’  
‘“$http\_user\_agent” “$http\_x\_forwarded\_for”’;

```
access_log /var/log/nginx/access.log main;

sendfile on;
keepalive_timeout 65;

gzip on;
gzip_min_length 1100;
gzip_buffers 4 8k;
gzip_types text/html text/plain text/xml text/javascript

```

text/css

```
charset utf-8;
upstream_fair_shm_size 64k;

upstream mongrel {
    server 127.0.0.1:8000;
    server 127.0.0.1:8001;
}
server { ...
location / {
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;
    proxy_redirect false;

    if (-f $request_filename/index.html) {
       rewrite (.*) $1/index.html break;
    }
    if (-f $request_filename.html) {
       rewrite (.*) $1.html break;
    }
    if (!-f $request_filename) {
       proxy_pass http://mongrel;
       break;
    }
}
... }

```

## }

Everything is perfect and as expected, except handling of errors that  
come from mongrel. There are a few referring sites that overload the  
error.log of Nginx with errors like these:

* * *

proxy: Error reading from remote server returned by /some/path referer:  
[http://somesite.com](http://somesite.com)

## (70014)End of file found: proxy: error reading status line from remote server localhost, referer:

For a period of 30min. the error.log reaches ~500MB of those errors.

## If I access a mongrel\_instance directly with the same problematic request I get this from the instance output (not logs):

## Sun Aug 17 12:14:43 +0300 2008: HTTP parse error, malformed request (127.0.0.1): #\<Mongrel::HttpParserError: Invalid HTTP format, parsing fails.\>

It’s obvious where the problem is with mongrel, however it overloads the  
whole server with Nginx error logs and CPU load.

I got similar problems when using Apache as proxy\_balancer, however the  
rate of logs is far slower, so it doesn’t overload the server.

Any help or idea will be appreciated. I’m sure that our application  
deployment isn’t so unique, so someone else should have had the same  
problem.