This bug has been copied from bug #697310 and has been proposed to be backported to 5.7 z-stream (EUS).
Fix built into xen-3.0.3-132.el5_7.1
Verified with xen-3.0.3-132.el5_7.1. Test env setup: 2 hosts of RHEL5.7.z x86_64: kernel: kernel-xen-2.6.18-274.5.1.el5 Network card: Intel Corporation 82566DM-2 Gigabit Network, driver: e1000e xen: xen-3.0.3-132.el5_7.1 Guest RHEL5.7.z x86_64 PV guest: kernel: kernel-xen-2.6.18-274.5.1.el5 [1] Connect the 2 hosts with a crossover cable [2] Configure the 2 hosts to use static ip and set MTU=9000, like this # cat /etc/sysconfig/network-scripts/ifcfg-eth0 DEVICE=eth0 HWADDR=00:23:AE:6F:F6:3D BOOTPROTO=static IPADDR=192.168.0.1 NETMASK=255.255.255.0 MTU=9000 ONBOOT=yes eth0 is the interface connect to the crossover cable, and xen bridge connects to eth0: # cat /etc/xen/xend-config.sxp (network-script 'network-bridge netdev=eth0 bridge=xenbr0') similar configuration on the other host. [3] install the PV guest, update kernel to zstream kernel and configure the virtual nic to use static ip (in the same subnet of host) and MTU=9000, guest is using xenbr0. [4] boot up the PV guest with the configuration in step [3]. [5] migrate the guest between the 2 hosts. Test result: 1. After step [2], the interfaces eth0, peth0 and xenbr0 shows up with MTU=9000 in ifconfig output. 2. After step [4], the interface of backend vif has MTU=9000 in Dom0 (e.g. vif2.0)ifconfig output. The ifconfig output within DomU aslo has MTU=9000 for frontend interface (e.g. eth0) too. 3. After step [5], the interface of backend vif on the destination host has MTU=9000 in Dom0 (e.g. vif2.0)ifconfig output. The ifconfig output within DomU aslo has MTU=9000 for frontend interface (e.g. eth0) too.
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. http://rhn.redhat.com/errata/RHSA-2011-1401.html