[55386] in Hotline Meeting
Log # 218422 more analysis of Intaglio problem
daemon@ATHENA.MIT.EDU (Larry Stone)
Fri Jun 15 20:24:29 2001
Date: Fri, 15 Jun 2001 20:24:25 EDT
From: Larry Stone <lcs@MIT.EDU>
Reply-To: <lcs@MIT.EDU>
To: hotline@MIT.EDU, ds-sys@MIT.EDU
Message-ID: <CMM.0.90.4.992651065.lcs@defiant.mit.edu>
With Bill Guarente's help today I gathered more data about the problem.
I'm inclined to think there is something wrong with the network wiring
or the hub.
We were able to observe the hub, in a data closet next door to Doc Services.
It is an Asante AH2072 numbered "E219 18.51.1.105".
During a test that copied many Mb of large images files _from_ Intaglio
to a Windows NT box, the Asante hub showed an ethernet utilization rate
of about 50%, sometimes briefly lighting the 65%+ light. Before the
test the utilization was very low, 0-5%.
Also during the test, the hub's collision rate indicator varied between
3-10%. It spiked above that a couple times but mostly stayed under 10%.
Meanwhile, I was running "netstat -i 10" on intaglio to monitor
packets, errors, and collisions counted every 10sec. It showed a
collision rate seen by the host of about 50%, and an "output error"
rate of about 10%. Those figures are very pathological. If the Sun
and the hub are seeing different collision rates, perhaps the wiring
has problems?
The Sun didn't log any console diagnostics during this testing, but
earlier in the day it did have some "no carrier" complaints and
lost response from AFS file servers. That may have been
due to cables being moved around for testing however.
I recommend the following:
1. Has the twisted-pair cable from Intaglio to the network drop been
swapped out yet? I just assumed this had been tried, since Lou eliminated
a transciever that attached to the Sun's AUI port and translated to 10baseT,
which was unnecessary as it has a 10baseT port built-in. If not, try
swapping with a known good cable, possibly from one of the PCs.
2. Can VDIST test the drops and monitor them while a PC is
exercising the problem to look for electrical problems?
Perhaps there is a wiring problem that only shows up under load.
