Re: Slow NFS or slow NIC?
On Tue, Jan 11, 2000 at 11:26:05AM +1030, John Pearson wrote:
> On Mon, Jan 10, 2000 at 11:20:06PM +0100, Carel Fellinger wrote
> > using ncftp I get the expected 1.0+MBs transfer copying a large file into
> > /dev/null. Quite reasonable on a 10Mbs ethernet considering ftp and tcp each
> > adding their things. But if I do dd -if=/home/biggy of=/dev/null it takes
> > 10 times more then doing it locally and only fills a little more than
> > half the ethernet bandwith! how come? would it help to switch to 100Mbs
> > Ethernet? or has nfs so much overhead (but ftp does okee)? or is the 486
> > the culprit?
> >
>
> NFS is stateless and thus has significantly higher overhead than
> (say) ftp (although, being stateless has its advantages - you
> can reboot the server and suffer nothing worse than a long pause).
Okee, so there is more overhead. So more bytes have to be transfered.
But almost doubling it seems a bit overdone, doesn't it. So I'm still
wondering... Is the overhead mainly in the extra bytes to be sent,
then a 100Mbs Ethernet card would improve things. Or is the overhead
also in the pre/post processing, so a faster computer is wat's needed?
--
groetjes, carel
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