Veritas-bu

[Veritas-bu] max throughput of 20 Mbit per sec to tape ...

2004-06-30 08:58:24
Subject: [Veritas-bu] max throughput of 20 Mbit per sec to tape ...
From: William.Enestvedt AT jwu DOT edu (William Enestvedt)
Date: Wed, 30 Jun 2004 08:58:24 -0400
I saw Samuel Coco's suggestion to Rob DeLanghe to consider his SUn's
network link, and the advice not to auto-negotiate.
   I would like to point out that, while this has always been my
experience on Suns, too, recently I have heard from Sun support staff
that the newer ethernet controllers (e.g., dmfe) are "better" and should
be allowed to autonegotiate.
   Of course, any failures are still due to the switch. (Naturally.) And
when I remind the phone guys about Sun's old position of "only suckers
autonegotiate" and how it's still all over their InfoDocs and support
site, I can hear feet shifting under the chair and a lot of
throat-clearing. :7)
   I snorted derisively the first time they told me this -- but I have
recently experienced a rash of half a dozen different Sun Fire V100s
whose dmfe NICs have dropped to half-duplex despite being forced at the
switch and via the /platform/(I_forget)/kernel/drv/dmfe.conf file. Since
setting one to autonegotiate, its problem has gone. [Last night, though,
on a freshly-patched V100 running Solaris 8, the dmfe dropped to
half-duplex the very second the NBU job kicked off!]
    So, I, too, am reconsidering the old received wisdom of never
autonegotiating, and experimenting with it.
-wde
P.S. Rob, play with the buffer sizes before you do anythying else.
Search the Media Server's logs for messages about waiting for an empty
or a full buffer, and you'll know which way to go. A 280R should be able
to keep up with an L25: I have a li'l V120 driving an L25 with a single
SDLT 220 drive in it, and I usually get a good 10 Mb.
--
Will Enestvedt
UNIX System Administrator
Johnson & Wales University -- Providence, RI


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