From: "Chris Friesen" <cfriesen@nortel.com>
To: Rick Jones <rick.jones2@hp.com>
Cc: linux-kernel@vger.kernel.org,
Linux Network Development list <netdev@vger.kernel.org>
Subject: Re: dhcp-based netboot over jumbo-frame network?
Date: Wed, 08 Apr 2009 16:10:34 -0600 [thread overview]
Message-ID: <49DD20DA.3020902@nortel.com> (raw)
In-Reply-To: <49DCF7E2.2060304@hp.com>
Rick Jones wrote:
> Chris Friesen wrote:
>> We have an existing system that loads a bare kernel using tftp, then
>> mounts a rootfs via NFS. The wrinkle is that this is on a jumbo-frame
>> enabled network, so somehow the MTU needs to be set before mounting the
>> rootfs.
>
> Why? Is the NFS mount not TCP? If it is TCP, then the TCP MSS exchange will
> provide you cover as it will (should) cause TCP in the NFS server to segment to
> the MSS option your system with the then-smaller MTU sends.
>
> I would think that only if the NFS mount is UDP that you would have a problem
> with the system initially booting with a small MTU.
Currently it uses the default, which is udp. I might be able to get
them to try TCP. Thanks for the suggestion.
>> In a previous version we patched ipconfig.c to support the DHCP option
>> to specify the MTU value, but I'm wondering about the "proper" way to do
>> this on current kernels.
>
> Was the change submitted to upstream and rejected?
The change was submitted (not by us) back in the 2.6.10 timeframe, and
was rejected with the suggestion to use initramfs.
Chris
prev parent reply other threads:[~2009-04-08 22:10 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-08 17:52 dhcp-based netboot over jumbo-frame network? Chris Friesen
2009-04-08 19:15 ` Rick Jones
2009-04-08 22:10 ` Chris Friesen [this message]
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