NFS Buffering

Simon Andrews simon.andrews at
Tue Sep 28 14:07:25 UTC 2010

I have a fedora 13 box on which I have a remote mounted nfs share over a 
fairly slow (10Mb/s) link.  I'm then transferring data onto this share 
from a different machine using scp.

The problem is that after scp reports that it's 100% complete the 
program will hang for ~20 mins before it will move on to another file. 
At this point it can't be killed.

It looks like the nfs daemon is caching write data (around 2GB of it) 
which lets scp think its finished when actually there's loads of data 
sitting in a write buffer.  The hanging is presumably the time it takes 
to flush the buffer (there is a process called nfsiod which is active 
during this time and df shows data is still being written).

Does anyone know how to either make this buffer smaller, or get rid of 
it all together so the scp can accruately report on its progress?



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