Date: Sat, 2 Aug 1997 12:00:20 -0500 From: Dan Nelson <dnelson@emsphone.com> To: Joao Carlos Mendes Luis <jonny@mailhost.coppe.ufrj.br> Cc: hackers@FreeBSD.ORG Subject: Re: NFS Problems in 2.2 ? Message-ID: <19970802120020.37958@dan.emsphone.com> In-Reply-To: <199708020734.EAA06531@zeus.coppe.ufrj.br>; from "Joao Carlos Mendes Luis" on Sat Aug 2 04:34:30 GMT 1997 References: <199707291925.QAA09968@gaia.coppe.ufrj.br> <199708020734.EAA06531@zeus.coppe.ufrj.br>
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In the last episode (Aug 02), Joao Carlos Mendes Luis said: > Just in case this can help. I lowered the speed of the NIC to 10M, > and got no more problems. > > If this is not a problem with the 100Mbps code (is it different ???), > surely is a problem with packet loss. > > #define quoting(Joao Carlos Mendes Luis) > // I'm having lots of problems with NFS deadlocks in my recent > // configuration. Both client and server are 2.2-STABLE, with 3c905 > // 100Mbps ethernet boards. Right now, for example, I have a netscape > // and am elm locked. If this helps, here's the output of a "ps > // -axlww | grep nfs" on the client: The 3c905 is just a low-quality card. Check out http://www.3com.com/0files/products/dsheets/400243.html, and look at the "Transmit/Receive Buffer Memory" section. It has an 8k buffer, partitioned by default at 4k xmit, 4k recv. At 100Mbps, the card will never be able to receive a full 8k NFS packet without dropping a fragment. NFS retries by resending the entire 8k packet, and that's where your deadlocks are coming from. At 10Mbps, the card is able to process an entire 8K packet, so your deadlock disappears. You can try mounting the NFS volumes with -r1024,-w1024,-I512, which will force 1K NFS packets. You might want to try another network card, if you can. The DEC 21140-based cards are supposed to be good, and the Intel EtherExpress Pro 10/100B is also a good card. I can sustain 4MB/s reads over NFS from a P6/200 server to a P133 client with 100B cards in both machines. -Dan Nelson dnelson@emsphone.com
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