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RE: [Xen-users] XCP ethernet jumbo frames????

To: Gémes Géza <geza@xxxxxxxxxxx>, <xen-users@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-users] XCP ethernet jumbo frames????
From: "James Harper" <james.harper@xxxxxxxxxxxxxxxx>
Date: Tue, 21 Sep 2010 08:27:45 +1000
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Thread-index: ActY98V9vUpZMof3RGSypvtONh36/QAGwxHg
Thread-topic: [Xen-users] XCP ethernet jumbo frames????
> Hi,
> I have an XCP 0.5 box running a few DomUs some of the DomU's data is
> stored at (clustered lvm volumes on) a Coraid etherdrive box which is
> connected via an Ethernet cable to a dedicated card of the XCP box, for
> which in the network config I' ve specified: MTU=9344: xe
> network-param-list uuid=.... gives:
> MTU ( RW): 9344
> on the DomUs if I leave the MTU at 1500 (default settings) everything
> works (slowly, but works). If I increase the MTU the aoe device appear
> as expected, but the data on it becomes inaccessible, even just trying
> to activate the lvm volume groups gives a bunch of IO errors at sector
> 0, and so on.
> Please tell me what I'm doing wrong. Are jumbo frames expected et all to
> work?

Does your network adapter really support jumbo frames?
Is the network adapter on a bridge? (I'm unsure if Dom0 does AoE or if the 
DomU's do)
Are all the bridge interfaces set to 9344 MTU?
Could tcp offload settings break any of this? (unlikely - AOE is not TCP)

tcpdump might tell you what's going on.


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