* Chuck Lever (2009-04-20): > On Apr 20, 2009, at 5:14 AM, André Berger wrote: >> * Chuck Lever (2009-04-17): >>> Copying linux-nfs@xxxxxxxxxxxxxxx, please follow up there. >> >> OK, here we go. If anyone here doesn't want to receive these >> messages, please let me know. >> >> It took me a while to get a tcpdump binary for the dbox2, hence the >> delay and extensive quotes. The libc6 for tcpdump is itself located >> on a NFS share. > > [ ... ] > >>> You could try capturing a raw packet trace of the initial mount and a >>> few >>> reads and write on the share. The clients negotiate the rsize and >>> wsize >>> settings with the server, and the packet dump would expose the >>> negotiated >>> values. >>> >>> On your clients, use "tcpdump -s 0 -w /tmp/raw host" followed by the >>> DNS >>> name of your server. Then attach the raw pcap files to e-mail (as >>> long as >>> they are less than 100KB or so) and post them to linux-nfs@xxxxxxxxxxxxxxx >> >> Here you go. The host "192.168.1.8 hg linkstation" is specified in >> /etc/hosts. >> >>>> For the sake of completeness, my router is a Linksys WRT54G >>>> >>>> with Tomato firmware >>>> >>>> <http://www.polarcloud.com/tomato_123> >>>> >>>> and a MTU of 1492 throughout the network. >>>> >>>> If there is anything I can do to help troubleshooting, please let me >>>> know. > > I got two copies of this e-mail. One has a 24KB PCAP file called "raw" > and the other has a 90KB file called "xap" that does not appear to be a > PCAP file. The first message was too big for the list and bounced (172 KB). For the second one (90KB raw size), I was unable to produce a dump small enough, so I used split on it. I might have sent the wrong part though. > I looked at "raw" and it's hard to make sense of it. I see both UDP and > TCP traffic, and both NFSv2 and NFSv3 requests. I guess this is because > tcpdump is on NFS. It would be better if you could copy the tcpdump > binary to a local file system on the client before running the test to > avoid the extra traffic. Space is very limited on the dbox, so I had to try and compile the dbox2 Neutrino OS with tcpdump during the last couple of days. Yesterday I succeeded, so I hope to boot the beast today. > You should avoid UDP on this network at all costs, especially if you want > to use large r/wsize. It's likely that this is the real performance > issue. Specify "proto=tcp" on your mount command line to force the use of > NFS/TCP. Otherwise IP packet fragmentation and reassembly will cause > dropped RPC requests, exacerbated by network link speed mismatches and > Ethernet frame collision on the half-duplex links. > > I believe the older 2.4-based NFS clients will use UDP by default. Weird, I always got the best results with UDP for writing and TCP for reading. I'll try and produce a better, short tcpdump as soon as I can. -André -- May as well be hung for a sheep as a lamb! Linkstation/KuroBox/HG/HS/Tera Kernel 2.6/PPC from <http://hvkls.dyndns.org> iPhone <http://hvkls.dyndns.org/downloads/documentation/README-iphone.html> -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
