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Re: Nginx TCP Delays

Maxim Dounin
September 21, 2009 12:52PM
Hello!

On Mon, Sep 21, 2009 at 09:26:22AM -0700, Khalid Shaikh wrote:

> Team,
> Here is another sample point. See the 9 second delay on the server I keep
> speaking about. This problem shows across multiple servers. The one we are
> investigating is http://67.159.60.59/status. Same nginx.conf across all.
>
> root@pa:~# clear; ./status.rb
> Active connections: 17442
> server accepts handled requests
> 291457 291457 499538
> Reading: 242 Writing: 3838 Waiting: 13362
> http://208.53.158.42/status 0.07 seconds
>
> Active connections: 11545
> server accepts handled requests
> 8720635 8720635 13904180
> Reading: 154 Writing: 1370 Waiting: 10021
> http://67.159.60.37/status 0.03 seconds
>
> Active connections: 3807
> server accepts handled requests
> 3758087 3758087 27448407
> Reading: 44 Writing: 213 Waiting: 3550
> http://66.90.101.97/status 0.04 seconds
>
> Active connections: 8855
> server accepts handled requests
> 6865763 6865763 10978021
> Reading: 133 Writing: 988 Waiting: 7734
> http://208.53.158.75/status 0.03 seconds
>
> Active connections: 10571
> server accepts handled requests
> 194174 194174 467424
> Reading: 106 Writing: 2147 Waiting: 8318
> http://67.159.60.59/status 9.03 seconds

After looking closely on timings you provide - it's
suspiciously rounded delays. Looks like packet
drops/retransmissions. This may be due to some network resource
shortage on the host in question or some problems on the wire.

First of all, try tcpdump to see what actually happens on the
wire.

Also it's probably a good idea to examine your backlog size and
status. AFAIK Linux by default just drops incoming SYN packets on
listen queue overflows, so this may be the reason.

Maxim Dounin

>
> Active connections: 8354
> server accepts handled requests
> 4314517 4314517 6679147
> Reading: 195 Writing: 1954 Waiting: 6205
> http://208.53.158.200/status 0.03 seconds
Subject Author Posted

Nginx TCP Delays

Khalid Shaikh September 21, 2009 01:52AM

RE: Nginx TCP Delays

Brian Henson September 21, 2009 03:38AM

Re: Nginx TCP Delays

Khalid Shaikh September 21, 2009 03:46AM

Re: Nginx TCP Delays

François Battail September 21, 2009 04:06AM

Re: Nginx TCP Delays

Khalid Shaikh September 21, 2009 04:22AM

Re: Nginx TCP Delays

Khalid Shaikh September 21, 2009 04:24AM

Re: Nginx TCP Delays

François Battail September 21, 2009 04:58AM

Re: Nginx TCP Delays

Khalid Shaikh September 21, 2009 12:08PM

Re: Nginx TCP Delays

Avleen Vig September 23, 2009 04:52AM

Re: Nginx TCP Delays

François Battail September 23, 2009 11:22AM

Re: Nginx TCP Delays

Christopher Smith September 24, 2009 03:50AM

Re: Nginx TCP Delays

Khalid Shaikh September 24, 2009 11:22AM

Re: Nginx TCP Delays

icqheretic October 05, 2009 03:09PM

Re: Nginx TCP Delays

anomalizer October 03, 2009 03:34AM

Re: Nginx TCP Delays

Maxim Dounin September 21, 2009 04:50AM

Re: Nginx TCP Delays

Khalid Shaikh September 21, 2009 04:58AM

Re: Nginx TCP Delays

Khalid Shaikh September 21, 2009 12:32PM

Re: Nginx TCP Delays

Maxim Dounin September 21, 2009 12:52PM

Re: Nginx TCP Delays

Khalid Shaikh September 21, 2009 02:08PM

Re: Nginx TCP Delays

Khalid Shaikh September 21, 2009 03:44PM

Re: Nginx TCP Delays

Khalid Shaikh September 22, 2009 12:30AM

Re: Nginx TCP Delays

Payam Chychi September 22, 2009 02:24AM



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