Linux kernel tuning TCP/Memcached

[me-5yx05kfkO/aqeI1yJSURBw at public.gmane.org (Matthew Gillen)]

On 08/02/2010 07:59 PM, Dan Ritter wrote:
> http://lartc.org/howto/lartc.kernel.obscure.html
> 
> excerpt:
> 
>     /proc/sys/net/ipv4/tcp_tw_recycle
> 
>     Enable fast recycling TIME-WAIT sockets. Default value is 1.
>     It should not be changed without advice/request of technical
>     experts.
> 
> Nevertheless, it seems to be set to zero by default on most
> distros.
>
> Hrm. Warrants further investigation.

Indeed.  A little more digging turned up this:

http://www.speedguide.net/read_articles.php?id=121
--------------------------------------
TCP_TW_RECYCLE
It enables fast recycling of TIME_WAIT sockets. The default value is 0
(disabled). The sysctl documentation incorrectly states the default as
enabled. It can be changed to 1 (enabled) in many cases. Known to cause some
issues with hoststated (load balancing and fail over) if enabled, should be
used with caution.

    echo 1 > /proc/sys/net/ipv4/tcp_tw_recycle
    (boolean, default: 0)
--------------------------------------

It always surprises me how little documentation there is for many kernel
parameters...

Matt