Weird 0.8.11.1 connections spike

[Jim Ohlstein]

Igor Sysoev wrote:
> On Sun, Aug 30, 2009 at 01:45:30AM +1000, Jeff Waugh wrote:
>
>   
>> <quote who="Igor Sysoev">
>>
>>     
>>>> 2009/08/29 23:15:52 [alert] 8716#0: open socket #152 left in connection 105
>>>>         
>>> This is probably after reconfiguraiton.
>>>       
>> Sorry, yes, I should've checked the time -> that was from when I reverted to
>> 0.8.10... there no alerts prior to that.
>>
>>     
>>> There are signinficant changes in 0.8.11, but you case is strange: I'am
>>> testing 0.8.11 on a host with 400r/s with a lot of proxied SSIed
>>> subrequests and static files, and there is no connection leak.
>>>
>>> Have you built any third party modules ?
>>>       
>> None.
>>
>> btw, the majority of my non-static traffic is fastcgi over unix socket. I'm
>> going to do the upgrade again and watch the activity.
>>     
>
> Could you do the following:
>
> 1) enable coredumps
> 2) set in nginx.conf:
>    debug_points  abort;
> 3) reconfigure nginx, if there are open connections, then nginx creates
>    coredump on exit
> 4) look in log for alerts: open socket #... left in connection NN
> 5) run "gdb /path/to/nginx /path/to/core", then
>
>    p ((ngx_connection_t *) ngx_cycle->connections[NN]->data)->uri
>    p ((ngx_connection_t *) ngx_cycle->connections[NN]->data)->main->count
>
>    do not forget to set NN from log message.
>
>
>   
Igor,

On one server I seem to be seeing the same issue. Twice since upgrading 
to 0.8.11 I have found the site unresponsive. It's a relatively slow 
vBulletin site on a very small VPS. We serve a fair bit of static 
content (photos mostly) and PHP via fastcgi.

OS is CentOS 5.3 Linux  - 2.6.18-028stab062.3

sample of error log (it grew to 36 GB in a few hours):

2009/08/30 07:50:20 [alert] 2043#0: accept() failed (24: Too many open 
files)
2009/08/30 07:50:20 [alert] 2043#0: accept() failed (24: Too many open 
files)
2009/08/30 07:50:20 [alert] 2043#0: accept() failed (24: Too many open 
files)
2009/08/30 07:50:20 [alert] 2043#0: accept() failed (24: Too many open 
files)
2009/08/30 07:50:20 [alert] 2043#0: accept() failed (24: Too many open 
files)
2009/08/30 07:50:20 [alert] 2043#0: accept() failed (24: Too many open 
files)

...

2009/08/30 10:29:00 [alert] 2042#0: accept() failed (24: Too many open 
files)
2009/08/30 10:29:00 [alert] 2042#0: accept() failed (24: Too many open 
files)
2009/08/30 10:29:00 [alert] 2042#0: accept() failed (24: Too many open 
files)
2009/08/30 10:29:00 [alert] 2042#0: accept() failed (24: Too many open 
files)
2009/08/30 10:29:00 [alert] 2042#0: accept() failed (24: Too many open 
files)
2009/08/30 10:29:00 [alert] 2042#0: accept() failed (24: Too many open 
files)
2009/08/30 10:29:00 [alert] 2042#0: accept() failed (24: Too many open 
files)
2009/08/30 10:29:00 [alert] 2042#0: accept() failed (24: Too many open 
files)
2009/08/30 10:29:00 [alert] 2042#0: accept() failed (24: Too many open 
files)

When I did shut it down I saw hundreds of lines like:

2009/08/30 10:29:00 [alert] 2042#0: open socket #1010 left in connection 
1002
2009/08/30 10:29:00 [alert] 2042#0: open socket #981 left in connection 1003
2009/08/30 10:29:00 [alert] 2042#0: open socket #994 left in connection 1004
2009/08/30 10:29:00 [alert] 2042#0: open socket #1017 left in connection 
1005
2009/08/30 10:29:00 [alert] 2042#0: open socket #1012 left in connection 
1006
2009/08/30 10:29:00 [alert] 2042#0: open socket #1011 left in connection 
1007
2009/08/30 10:29:00 [alert] 2042#0: open socket #1016 left in connection 
1008
2009/08/30 10:29:00 [alert] 2042#0: open socket #1014 left in connection 
1009
2009/08/30 10:29:00 [alert] 2042#0: open socket #1019 left in connection 
1010
2009/08/30 10:29:00 [alert] 2042#0: open socket #1020 left in connection 
1011
2009/08/30 10:29:00 [alert] 2042#0: open socket #1013 left in connection 
1012
2009/08/30 10:29:00 [alert] 2042#0: open socket #995 left in connection 1013
2009/08/30 10:29:00 [alert] 2042#0: open socket #988 left in connection 1014
2009/08/30 10:29:00 [alert] 2042#0: open socket #1023 left in connection 
1015
2009/08/30 10:29:00 [alert] 2042#0: aborting

Other servers seem to be running fine including ones with busy sites. 
For the moment I have reverted that VPS to 0.8.10.

Jim