Date: Tue, 2 Nov 2004 10:56:02 -0800 (PST) From: Doug White <dwhite@gumbysoft.com> To: Robert Watson <rwatson@freebsd.org> Cc: freebsd-current@freebsd.org Subject: Re: asymmetric NFS transfer rates Message-ID: <20041102105534.K63929@carver.gumbysoft.com> In-Reply-To: <Pine.NEB.3.96L.1041102131322.21044C-100000@fledge.watson.org> References: <Pine.NEB.3.96L.1041102131322.21044C-100000@fledge.watson.org>
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On Tue, 2 Nov 2004, Robert Watson wrote: > > On Tue, 2 Nov 2004, Emanuel Strobl wrote: > > > It's a IDE Raid controller (3ware 7506-4, a real one) and the file is > > indeed huge, but not abnormally. I have a harddisk video recorder, so I > > have lots of 700MB files. Also if I copy my photo collection from the > > server it takes 5 Minutes but copying _to_ the server it takes almost 15 > > Minutes and the average file size is 5 MB. Fast Ethernet isn't really > > suitable for my needs, but at least the 10MB/s should be reached. I > > can't imagine I get better speeds when I upgrade to GbE, (which the > > important boxes are already, just not the switch) because NFS in it's > > current state isn't able to saturate a 100baseTX line, at least in one > > direction. That's the real anstonishing thing for me. Why does reading > > staurate 100BaseTX but writes only a third? > > Have you tried using tcpdump/ethereal to see if there's any significant > packet loss (for good reasons or not) going on? Lots of RPC retransmits > would certainly explain the lower performance, and if that's not it, it > would be good to rule out. The traces might also provide some insight > into the specific I/O operations, letting you see what block sizes are in > use, etc. I've found that dumping to a file with tcpdump and reading with > ethereal is a really good way to get a picture of what's going on with > NFS: ethereal does a very nice job decoding the RPCs, as well as figuring > out what packets are related to each other, etc. It'd also be nice to know the mount options (nfs blocksizes in particular). -- Doug White | FreeBSD: The Power to Serve dwhite@gumbysoft.com | www.FreeBSD.org
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