NFS Buffering

JB jb.1234abcd at gmail.com
Wed Sep 29 08:55:51 UTC 2010


Simon Andrews <simon.andrews <at> bbsrc.ac.uk> writes:

> 
> 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?
> 
> Thanks
> 
> Simon.
> 

Hi Simon,

you know, we are Linux users from Missouri USA here ...
Can you tell us what system your nfs server is installed on, how its exported
nfs shares are configured ?
Then we can gain some valuable clues regarding performance of all factors
involved.

JB




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