I'm running Xen 4.4.0 on Ubuntu 14.04. On this Dom0 I am running:
- 1 DomU Ubuntu 14.04 with Shorewall
- 1 DomU Windows Web Server 2008 R2 with GPL/PV drivers
Both domUs connect to the same bridge interface:
em1 -> vlan20 -> br20
The Ubuntu VM also connnects to other bridge interfaces and acts as a router/firewall between these vlans (each run a different subnet).
em1 -> vlan30 -> br30
em1 -> vlan40 -> br40
Performance is slow at irregular moments also during times of low use. I see a lot of dropped packets on these interfaces on the DomU
em1 Link encap:Ethernet HWaddr 00:25:90:e7:2d:82
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:133233517234 errors:0 dropped:446089 overruns:45378 frame:0
TX packets:85828527879 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:136901423025932 (136.9 TB) TX bytes:59904652719546 (59.9 TB)
Memory:dfa20000-dfa40000
br20 Link encap:Ethernet HWaddr 00:25:90:e7:2d:82
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:35528670 errors:0 dropped:2556 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:11419484087 (11.4 GB) TX bytes:0 (0.0 B)
br30 Link encap:Ethernet HWaddr 00:25:90:e7:2d:82
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:492 errors:0 dropped:41 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:21224 (21.2 KB) TX bytes:0 (0.0 B)
br40 Link encap:Ethernet HWaddr 00:25:90:e7:2d:82
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:1465977 errors:0 dropped:1422347 overruns:0 frame:0
TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:78070933 (78.0 MB) TX bytes:0 (0.0 B)
I think the dropped packets are due to the overruns shown on em1. I checked all components linked to my physical network and they all have the same uplink speed (1 Gb/s). The link speed on the Ubuntu VM is the same as on the Dom0 which is as expected however the link speed of the PGL PV NIC in windows is running 10 Gb/s.
Can this difference cause the overruns and if so, how can I force the GPL/PV driver to a lower link speed? (option is not available in the advanced adapter properties).
