After moving to 3.5 kernel I haven't seen it, even at 3x traffic which used
to cause it
On Mar 25, 2014 9:06 PM, Dewey McDonnell de...@poslinker.com wrote:
My web search reveals this problem has been around for years and most
posts conclude that the problem continues. After solving my tap0 TX
packets dropped problem, I find that my VM network has random freezes a
few times each day. Many bloggers on this subject say this VM network
freeze is difficult to reproduce. Not for me! I can cause a network
freeze on my VM in a heartbeat. Like many others, all I need to do is
start a data transfer over the bridge (FTP 2Kb file or larger). When the
freeze happens, ifconfig tap0 says overruns:1. This is QEMU version
1.6.2 without KVM on CentOS 6.5 version 2.6.32-431.
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report.
https://bugs.launchpad.net/bugs/997978
Title:
KVM images lose connectivity with bridged network
Status in OpenStack Compute (Nova):
Invalid
Status in qemu-kvm package in Ubuntu:
Fix Released
Status in qemu-kvm source package in Precise:
Fix Released
Bug description:
=
SRU Justification:
1. Impact: networking breaks after awhile in kvm guests using virtio
networking
2. Development fix: The bug was fixed upstream and the fix picked up in
a new
merge.
3. Stable fix: 3 virtio patches are cherrypicked from upstream:
a821ce5 virtio: order index/descriptor reads
92045d8 virtio: add missing mb() on enable notification
a281ebc virtio: add missing mb() on notification
4. Test case: Create a bridge enslaving the real NIC, and use that as
the bridge
for a kvm instance with virtio networking. See comment #44 for
specific test
case.
5. Regression potential: Should be low as several people have tested the
fixed
package under heavy load.
=
System:
---
Dell R410 Dual processor 2.4Ghz w/16G RAM
Distributor ID: Ubuntu
Description:Ubuntu 12.04 LTS
Release:12.04
Codename: precise
Setup:
-
We're running 3 KVM guests, all Ubuntu 12.04 LTS using bridged
networking.
From the host:
# cat /etc/network/interfaces
auto br0
iface br0 inet static
address 212.XX.239.98
netmask 255.255.255.240
gateway 212.XX.239.97
bridge_ports eth0
bridge_fd 9
bridge_hello 2
bridge_maxage 12
bridge_stp off
# ifconfig eth0
eth0 Link encap:Ethernet HWaddr d4:ae:52:84:2d:5a
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:11278363 errors:0 dropped:3128 overruns:0 frame:0
TX packets:14437384 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:4115980743 (4.1 GB) TX bytes:5451961979 (5.4 GB)
Interrupt:36 Memory:da00-da012800
# ifconfig br0
br0 Link encap:Ethernet HWaddr d4:ae:52:84:2d:5a
inet addr:212.XX.239.98 Bcast:212.XX.239.111
Mask:255.255.255.240
inet6 addr: fe80::d6ae:52ff:fe84:2d5a/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1720861 errors:0 dropped:0 overruns:0 frame:0
TX packets:1708622 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:210152198 (210.1 MB) TX bytes:300858508 (300.8 MB)
# brctl show
bridge name bridge id STP enabled interfaces
br0 8000.d4ae52842d5a no eth0
I have no default network configured to autostart in libvirt as we're
using bridged networking:
# virsh net-list --all
Name State Autostart
-
default inactive no
# arp
Address HWtype HWaddress Flags Mask
Iface
mailer03..com ether 52:54:00:82:5f:0f C
br0
mailer01..com ether 52:54:00:d2:f7:31 C
br0
mailer02..com ether 52:54:00:d3:8f:91 C
br0
dxi-gw2..comether 00:1a:30:2a:b1:c0 C
br0
From one of the guests:
domain type='kvm' id='4'
namemailer01/name
uuidd41d1355-84e8-ae23-e84e-227bc0231b97/uuid
memory2097152/memory
currentMemory2097152/currentMemory
vcpu1/vcpu
os
type arch='x86_64' machine='pc-1.0'hvm/type
boot dev='hd'/
/os
features
acpi/
/features
clock offset='utc'/
on_poweroffdestroy/on_poweroff
on_rebootrestart/on_reboot
on_crashdestroy/on_crash
devices
emulator/usr/bin/kvm/emulator
disk type='file' device='disk'
driver name='qemu' type='raw'/
source file='/dev/mapper/vg_main-mailer01--root'/
