Hello,
We're having a problem with Proxmox 2.1 and jumbo frames. Our network work uses an MTU of 9000. We're able to get PM 2.1 configured for this MTU, and the host is fine. After creating a VM however, the MTU on the bridge interface is dropped back down to 1500, and the guest is no longer able to reliably communicate.
Here is our interfaces file:
The guest we're trying to install, though I can't see how it would matter is CentOS 5.8, 64 bit. These are KVM VM's not OpenVZ.
After starting a VM, this is what our network config looks like:
Before the VM is created / started, the MTU on vmbr0 is 9000.
The problem appears to be the same as http://forum.proxmox.com/threads/7877-Jumbo-Frames-on-vmbr0, but thread is a little dated. I'm hoping there's a solution.
Thanks,
Kevin.
We're having a problem with Proxmox 2.1 and jumbo frames. Our network work uses an MTU of 9000. We're able to get PM 2.1 configured for this MTU, and the host is fine. After creating a VM however, the MTU on the bridge interface is dropped back down to 1500, and the guest is no longer able to reliably communicate.
Here is our interfaces file:
Code:
auto lo
iface lo inet loopback
iface eth0 inet manual
mtu 9000
iface eth1 inet manual
mtu 9000
auto bond0
iface bond0 inet manual
slaves eth0 eth1
auto vmbr0
iface vmbr0 inet static
address 192.168.45.104
netmask 255.255.255.0
gateway 192.168.45.1
bridge_ports bond0
bridge_stp off
bridge_fd 0
#mtu 9000
pre-up ifconfig bond0 mtu 9000
The guest we're trying to install, though I can't see how it would matter is CentOS 5.8, 64 bit. These are KVM VM's not OpenVZ.
After starting a VM, this is what our network config looks like:
Code:
ifconfig
bond0 Link encap:Ethernet HWaddr d4:be:d9:b3:92:62
inet6 addr: fe80::d6be:d9ff:feb3:9262/64 Scope:Link
UP BROADCAST RUNNING MASTER MULTICAST MTU:9000 Metric:1
RX packets:3912101 errors:0 dropped:0 overruns:0 frame:0
TX packets:1168381 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:816034347 (778.2 MiB) TX bytes:237400007 (226.4 MiB)
eth0 Link encap:Ethernet HWaddr d4:be:d9:b3:92:62
UP BROADCAST RUNNING SLAVE MULTICAST MTU:9000 Metric:1
RX packets:1952418 errors:0 dropped:0 overruns:0 frame:0
TX packets:585542 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:407415542 (388.5 MiB) TX bytes:118722536 (113.2 MiB)
Interrupt:36 Memory:d6000000-d6012800
eth1 Link encap:Ethernet HWaddr d4:be:d9:b3:92:62
UP BROADCAST RUNNING SLAVE MULTICAST MTU:9000 Metric:1
RX packets:1959683 errors:0 dropped:0 overruns:0 frame:0
TX packets:582839 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:408618805 (389.6 MiB) TX bytes:118677471 (113.1 MiB)
Interrupt:48 Memory:d8000000-d8012800
lo Link encap:Local Loopback
inet addr:127.0.0.1 Mask:255.0.0.0
inet6 addr: ::1/128 Scope:Host
UP LOOPBACK RUNNING MTU:16436 Metric:1
RX packets:294585 errors:0 dropped:0 overruns:0 frame:0
TX packets:294585 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:32061297 (30.5 MiB) TX bytes:32061297 (30.5 MiB)
tap100i0 Link encap:Ethernet HWaddr 22:6d:2d:89:e5:4c
inet6 addr: fe80::206d:2dff:fe89:e54c/64 Scope:Link
UP BROADCAST RUNNING PROMISC MULTICAST MTU:1500 Metric:1
RX packets:2279 errors:0 dropped:0 overruns:0 frame:0
TX packets:805343 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:500
RX bytes:175269 (171.1 KiB) TX bytes:98670226 (94.0 MiB)
venet0 Link encap:UNSPEC HWaddr 00-00-00-00-00-00-00-00-00-00-00-00-00-00-00-00
inet6 addr: fe80::1/128 Scope:Link
UP BROADCAST POINTOPOINT RUNNING NOARP MTU:1500 Metric:1
RX packets:0 errors:0 dropped:0 overruns:0 frame:0
TX packets:0 errors:0 dropped:3 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)
vmbr0 Link encap:Ethernet HWaddr d4:be:d9:b3:92:62
inet addr:192.168.45.74 Bcast:192.168.45.255 Mask:255.255.255.0
inet6 addr: fe80::d6be:d9ff:feb3:9262/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:2064884 errors:0 dropped:0 overruns:0 frame:0
TX packets:1165110 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:460285304 (438.9 MiB) TX bytes:232322492 (221.5 MiB)
Before the VM is created / started, the MTU on vmbr0 is 9000.
The problem appears to be the same as http://forum.proxmox.com/threads/7877-Jumbo-Frames-on-vmbr0, but thread is a little dated. I'm hoping there's a solution.
Thanks,
Kevin.