Linux kernel tuning TCP/Memcached

[Matthew Gillen]

On 08/03/2010 07:35 PM, jc-8FIgwK2HfyJMuWfdjsoA/w at public.gmane.org wrote:
> 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
> -bash: /proc/sys/net/ipv4/tcp_tw_recycle: Permission denied
> : cat /proc/sys/net/ipv4/tcp_tw_recycle
> 1
> :

That same set of commands does not set tcp_tw_recycle on my machine, and
shouldn't work.  You must have done something in between, or have some strange
shell/alias thing going on (the sudo only applies to the 'echo 1' part, the
controlling shell handles the redirection, which is why you /should/ get the
permission denied, since the controlling shell doesn't get its privs escalated
by the sudo command).

>From the sudo man page:
> To make a usage listing of the directories in the /home partition.  Note that this runs the commands in a sub-shell to make the cd and file redirection
>        work.
> 
>         $ sudo sh -c "cd /home ; du -s * | sort -rn > USAGE"

Matt