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From: Eric Wong <e@80x24.org>
To: Jim Zhan <cjzhan2000@gmail.com>
Cc: unicorn-public@bogomips.org
Subject: Re: Unicorn configuration to increase max header size
Date: Fri, 21 Nov 2014 00:31:37 +0000	[thread overview]
Message-ID: <20141121003137.GA31484@dcvr.yhbt.net> (raw)
In-Reply-To: <CAD6h1mi0=2b-iScdD39yeMq7xcyHV7t_esVMHH9MZMDmThFPqQ@mail.gmail.com>

Jim Zhan <cjzhan2000@gmail.com> wrote:
> Hi Eric,
> Thank you for the quick reply. I checked out hosts and we are using Unicorn
> 3.4.1. Unfortunately there is only one setting for client_body_buffer_size.
> So how does this parameter work? Will it only put a limitation on the body
> itself or it applied proportionally to header and body (e.g., header 8k,
> body 104k, etc).

client_body_buffer_size in unicorn is only for request bodies (uploads),
and not relevant to header sizes.

> We did experiments using curl by sending header exceeding 8k manually and I
> am getting 404. So it's unicorn itself, not nginx that has the 8k header
> size limitation.

I suspect you're hitting the nginx large_client_header_buffers default
limit of 8K:


I checked the unicorn source, and ext/unicorn_http/global_variables.h
defines the maximum field value as 80K, 10 times more than what you're


This value was inherited from Mongrel many years ago and never changed.

> The command we used for the experiment:
> curl -v -H "$(./http-header-pumper.bat 8000)" <service_url>

I just tried your script with the following config.ru to hit unicorn
directly (no nginx), and I got the expected lobster response.

$ unicorn -E none config.ru
----------- config.ru -----------
require 'rack/lobster'
use Rack::ContentLength
run Rack::Lobster.new

  reply	other threads:[~2014-11-21  0:31 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-11-20 21:54 Unicorn configuration to increase max header size Jim Zhan
2014-11-20 21:59 ` Eric Wong
2014-11-20 23:35   ` Jim Zhan
2014-11-21  0:31     ` Eric Wong [this message]
2014-11-21  1:33       ` Jim Zhan
2014-11-22  3:15         ` Jim Zhan

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