[Atlas-anchors-pilot] HW specs: the choice of *two*

Aleksi Suhonen Aleksi.Suhonen at trex.fi
Fri Oct 12 03:11:54 CEST 2012 

Hello,

On 10/05/2012 07:43 PM, Martin Stanislav wrote:
> On Fri, Sep 28, 2012 at 02:13:05PM +0300, Aleksi Suhonen wrote:
>> On 09/27/2012 09:49 PM, Romeo Zwart wrote:
>>> The system proposed indeed includes an on-board Dual-port GE interface
>>> (Broadcom).

>> OK, so the MTU issue with this hardware still persists? Broadcom drivers
>> don't do jumbo frames reliably.

> Do the broadcom NIC drivers in general have problems delivering jumbo frames
> or your experience is specific to some OS platform&  driver combination,
> exceeeding particular frame size, any other feature in use (802.1Q tags)?

My experiences have been with Linux 2.6.3x and Linux 3.2.x with XEN and 
802.1Q tags. As long as the MTU settings are normal (untouched default 
values, 1500+tags) everything works fine. But if I set MTU to 9000 the 
driver will suddenly stop forwarding traffic after a random period of 
time. It seems to work at first, but then fails when you're not looking.

The driver in question is bnx2 and the chip in question is:

02:00.0 Ethernet controller: Broadcom Corporation NetXtreme II BCM5716 
Gigabit Ethernet (rev 20)

This is a concern to me, because if we get to host an anchor and if 
there will eventually be a K-root mirror on it, the K-root mirror will 
need to connect to our peering VLAN which has MTU 9000.

So please test the proposed hardware platform with this in mind and let 
me know if it's sturdy.

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	Aleksi Suhonen / TREX  Tampere Region Exchange Oy

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