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From: Willy Tarreau <w@1wt.eu>
To: Karl Pickett <karl.pickett@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>,
	linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: tcp_tw_recycle broken?
Date: Sat, 15 Nov 2008 16:52:28 +0100	[thread overview]
Message-ID: <20081115155228.GZ24654@1wt.eu> (raw)
In-Reply-To: <f9be06770811150747l574badc1l8d509baae4f81ac5@mail.gmail.com>

On Sat, Nov 15, 2008 at 10:47:10AM -0500, Karl Pickett wrote:
> On Sat, Nov 15, 2008 at 8:09 AM, Andi Kleen <andi@firstfloor.org> wrote:
> > "Karl Pickett" <karl.pickett@gmail.com> writes:
> >>
> >> May I just confirm.. is tcp_tw_reuse NOT dependent on receiving timestamps?
> >
> > The big problem is that both are incompatible with NAT. So if you
> > ever talk to any NATed clients don't use it.
> >
> > -Andi
> >
> > --
> > ak@linux.intel.com
> >
> 
> 
> Hmph.  Running the test again - after getting a little sleep -
> timestamps do indeed determine if tw_reuse/recyle work.  I must not
> have let all the tw buckets expire before changing my timestamp
> settings last night.
> 
> Since
> A. I don't want to rely on arbitrary web servers having timestamps
> B. People say it breaks NAT for clients, and the settings are global only,
> 
> I will just set TCP_TIMEWAIT_LEN to 10 seconds and call it a day.

you should increase it a bit. I've encountered occasional issues at 15s,
but none at 20s.

> Sure would be nice if it was a tunable, so only the most heavily
> loaded customers could set it...

Indeed. other OSes (eg Solaris) ship with standard values and let us adjust
them.

Willy


  reply	other threads:[~2008-11-15 15:52 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-11-15  4:37 tcp_tw_recycle broken? Karl Pickett
2008-11-15  5:57 ` Willy Tarreau
2008-11-15  7:29   ` Karl Pickett
2008-11-15 13:09     ` Andi Kleen
2008-11-15 15:47       ` Karl Pickett
2008-11-15 15:52         ` Willy Tarreau [this message]
     [not found]   ` <f9be06770811142325j79ca0831j7d5820716199811@mail.gmail.com>
2008-11-15  7:45     ` Willy Tarreau

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