[CentOS] Experiencing continual eth0 link up/down on a 10G Chelsio NIC (cxgb3 driver)

Hakan Koseoglu hakan at koseoglu.org
Mon Feb 8 18:55:03 UTC 2010

Hi Arun,

On Mon, Feb 8, 2010 at 6:43 PM, Arun Khan <knura9 at gmail.com> wrote:
> The file server has a Chelsio T310 10GBASE-CX4 RNIC (rev 3) PCI
> Express x8 MSI-X (eth0), driver and firmware is stock from the CentOS
> Plus kernel.
Way way back, I had similar problems on a bunch of servers with 3Com
cards and some 3Com switches.
It turns out to be the autonegotiation of the 3Com cards and switches
we got at that time were buggy and some idiot had set the switches to
100Mbit full duplex and the cards to autoneg and it kept initiating
autonegation and the buggy card kept on doing the wrong rate. The
result was poor performance and constant link down/up cycle.

It's worth checking what the switch side is set to. Also setting both
sides to a particular value might help or just remove all and leave
for autonegation.

> The hardware vendor tells me that the card either fails completely
> (kaput) or works - there is no grey area.  He is of the opinion that
> the problem is with the driver.
The last thing, IMHO, never trust a supplier trying to wriggle out of
a support case :) I've seen plenty of network cards that's on the way
but not dead yet.

Hakan (m1fcj) - http://www.hititgunesi.org

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