[Users] Configuring MTU

[Ayal Baron]

----- Original Message -----
> On Fri, 30 Mar 2012, Ayal Baron wrote:
> 
> > Have you encountered any issues with it? although the bond supports
> > 9000, sending a 1500 packet from the guest should work just fine.
> 
> Right, the issue I am having is larger then 1500 packet being sent to
> the
> guest.
> 
> > The only way I can think of to control this per guest would be to
> > configure the tap device of the vNIC, however, all devices
> > connected to a bridge have to have the same mtu so changing one
> > tap device would require changing them all which would beat the
> > purpose.
> > So I'm not sure what you're actually asking for here.
> 
> Today what I do is this. Fire up the VM, find out what host its on,
> figure
> out the vnet interface and then ifconfig it with smaller MTU if it is
> say
> vnet1 I would:
> 
> ifconfig vnet1 mtu 1500
> 
> This seams to be working, other hosts that have vnet interfaces at
> 9000
> bytes still work and nothing larger then 1500 bytes is sent to the
> vnet I
> lower to 1500. I now just need a way to keep from doing this every
> time
> manually.

So if I have 3 VMs that require 1500 and I have 3 hosts and they just happen to be scheduled one per host, my other 100 VMs that do support 9000 would be degraded.
Instead, separate these 3 VMs to a different vnet and everything just works.

When you change the vnet you're degrading all the VMs running on this host using this network.

> 
> -Nathan
>