Linux kernel tuning TCP/Memcached

[Nathan Meyers]

On Tue, Aug 03, 2010 at 07:35:39PM +0000, jc-8FIgwK2HfyJMuWfdjsoA/w at public.gmane.org wrote:
> Matthew Gillen wrote:
> | 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)
> | --------------------------------------
> 
> Hmmm ... I'm trying to explain this:
> 
> : cat /proc/sys/net/ipv4/tcp_tw_recycle
> 0
> : echo 1 > /proc/sys/net/ipv4/tcp_tw_recycle
> -bash: /proc/sys/net/ipv4/tcp_tw_recycle: Permission denied
> : sudo echo 1 > /proc/sys/net/ipv4/tcp_tw_recycle

The redirect is interpreted and performed (if you have write permission)
in the environment in which your current shell is running, not in the
privileged shell created by sudo. Strange that this worked at all.

Nathan





> -bash: /proc/sys/net/ipv4/tcp_tw_recycle: Permission denied
> : cat /proc/sys/net/ipv4/tcp_tw_recycle
> 1
> :
> 
> So it seems to have done it, despite the second error message. So I did a bit
> of  testing, and verified that apache still works the same as before.  Now to
> figure out whether I can stress test in on a "home"  ISP  connection  with  a
> not-very-fast upload speed.
> 
> 
> --
>    _'
>    O
>  <:#/>  John Chambers
>    +   <jc-8FIgwK2HfyJMuWfdjsoA/w at public.gmane.org>
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