Re: nfs is very slow
On Thursday 07 August 2003 14:01, Gregor Stößer wrote:
> I'm having some trouble with my nfs-server. Performance is very bad, but
> all ather protocols (ftp, http, scp) are quite fast.
ftp, http et al. use TCP connections while NFS per default uses UDP packets.
More recent kernels have experimental support for NFS over TCP. In your case
(fast network where latency is a very limiting factor), there might be a
problem with NFS sending small packages and needing confirmation on every
one, thus adding a huge overhead, while TCP scales better. If you find a way
to increase packet sizes - gigabit ethernet should support around 65kB -, you
might actually see a performance increase.
And something that got me: be sure you are not running IDS software like
snort, or if you need it, make sure it ignores NFS traffic. I had the problem
that after some two minutes of nfs use, my root partition was mysteriously
full. It turned out that snort wrote a detailed report on each and every
packet the server received. I don't know if this had any impact on
performance (relatively slow network), but I don't think a thing like this