Re: [lvs-users] Apparent MTU problem using LVS-DR and Windows 2003 RealS

To: " users mailing list." <lvs-users@xxxxxxxxxxxxxxxxxxxxxx>
Subject: Re: [lvs-users] Apparent MTU problem using LVS-DR and Windows 2003 RealServers
From: Graeme Fowler <graeme@xxxxxxxxxxx>
Date: Fri, 18 Sep 2009 11:48:08 +0100
On Thu, 2009-09-17 at 04:19 -0700, Christopher Smith wrote:
> From some more testing I've concluded that this appears to be VMware related. 
>  It only occurs when the client and the director are on both the same vSwitch 
> (or dvSwitch) and the same subnet.
> I'll take it up with VMware. :)

Just a momentary thought: if this is only occurring with "push"
transfers to realservers, then there may be some object in the L3 or L2
path which isn't capable of larger MTU and is disrupting the traffic

Are you, by any chance, using systems connected to a gigabit ethernet
network? This sounds to me like a possible issue with jumbo frames not
making it through something - or something like that.

Alternatively, have you switched off TCP checksum offloading? This has
been the cause of some problems in the past.


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