Re: [Planetlab-users] sysctl variables

[Neil S. <ns...@cs...>]

Manpreet,

On Nov 13, 2003, at 8:38 PM, Manpreet Singh wrote:
>    Sorry to bother everyone, but I am also new on planetlab.

I was told last month that this is the forum for new users to bother 
people and feel comfortable doing it.

> Am I allowed
> to change some sysctl variables? I tried 'su' on some nodes, but that
> also does not permit me to do this.

Being root in your vserver just lets you manipulate the filesystem, it 
doesn't let you reconfigure the kernel.  :(

>     In particular, I want to change the default send/receive window 
> sizes.
> I know that I can use setsockopt, but that is ultimately limited by the
> sysctl variables.

Your application should use setsockopt, because I don't expect any 
change to vservers will let you frob wmem_default or tcp_wmem.  there's 
still just one kernel and a large socket buffer would probably do my 
application harm.   (hmm, maybe I should even shrink it.)

It might be possible to increase [rw]mem_max, but that is a discussion 
for planetlab-arch or planetlab-support;  how large did you intend to 
configure? and can you tell that 132KB is too small?

-neil (no stranger to the joys of tcp window frobbing)