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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 
goes unpunished.

Got Backup?

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