Date: Wed, 21 Mar 2001 21:45:26 +0100 (CET) From: Jan Conrad <conrad@th.physik.uni-bonn.de> To: Helge Oldach <Helge.Oldach@de.origin-it.com> Cc: <bright@wintelcom.net>, <dillon@earth.backplane.com>, <gordont@bluemtn.net>, <rdm@cfcl.com>, <freebsd-stable@FreeBSD.ORG> Subject: Re: NFS performance Message-ID: <Pine.BSF.4.33.0103212133210.559-100000@merlin.th.physik.uni-bonn.de> In-Reply-To: <200103211955.UAA03416@galaxy.de.cp.philips.com>
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On Wed, 21 Mar 2001, Helge Oldach wrote:
> Jan Conrad:
> >client:
> >Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Coll
> >fxp0 1500 <Link#1> 00:02:b3:1f:f8:c5 1901001 0 771611 0 208240
> >server:
> >Name Mtu Network Address Ipkts Ierrs Opkts Oerrs Coll
> >fxp0 1500 <Link#1> 00:90:27:1c:f3:79 7157753 0 4648694 0 2661459
>
> Gimme a break. Out of 4648694 output packets you see as many as 2661459
> collisions? That's more than 50%, i.e. for about every second packet
> that you are sending you get a collision! You very clearly have a
> collision problem.
>
> I bet that the switch is at full-duplex while you're at half. Try
> changing the mediaopt setting of your NIC.
That's funny, eh :-)
ok - just collect some facts:
- the switch is configured to 100baseTX, half-duplex: BayStack 450 24T
(I am not the admin of that thing and have no access to the confs,
but at least I know how the ports are configured, unfortunately there
are no full/half duplex lights anymore on the newer Baystacks)
- if I leave it at half-duplex the net makes 9Mb/s
ping -f <Machine on the same switch) I get 0% to 1% packet loss
(after relaxing the icmp bandwidth control...)
- if I switch the fxp0 interface to full duplex
and boot the machine and disconnect the net for some seconds
the net slows down to 200kb/s
I would conclude that the switch is on 100baseTX, half-duplex, indeed.
again, running on half-duplex, transfering 100Mb from a client to this
machine (merlin)
on client:
mount -t nfs -o intr,nfsv3,-r=32768,-w=32768 merlin:/freebsd/misc /mnt
dd if=/dev/zero of=/mnt/zero bs=16k count=64x100
104857600 bytes transferred in 12.765062 secs (8214422 bytes/sec)
at the same time, netstat -I fxp0 -w 1 gives me
11 0 668 11 0 412 0
6 0 1670 5 0 1556 0
8 0 180 7 0 0 0
11 0 5155696 8 0 62530 0
254 0 7015588 23 0 98848 32
6115 0 7926312 540 0 118592 1189
input (fxp0) output
packets errs bytes packets errs bytes colls
5304 0 9183810 548 0 136772 1030
5768 0 8091074 586 0 120418 1139
6527 0 9191418 674 0 138720 1337
5915 0 8728739 612 0 129630 1176
6492 0 9032044 678 0 133856 1243
6195 0 8112222 634 0 122300 1237
6509 0 9251329 674 0 137258 1287
5886 0 8317303 605 0 125380 1138
6490 0 8904250 665 0 132046 1334
5978 0 8857169 617 0 139924 1149
6444 0 853656 676 0 23624 1259
4720 0 313 564 0 0 903
1 0 1349 1 0 1390 0
2 0 171 0 0 90 0
quite funny, but it works :-)
Has anybody ever seen something like that ?
>
> Helge
>
ciao
Jan
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