OVS 中的网卡 ovs-system

运行ovs后，Linux系统中会多出一块状态是down掉的网卡ovs-system：

ifconfig -a  
...
ovs-system Link encap:Ethernet  HWaddr FA:4F:0D:E4:DA:11  
          BROADCAST MULTICAST  MTU:1500  Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:6 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0 
          RX bytes:0 (0.0 b)  TX bytes:468 (468.0 b)
...

历史原因，Open vSwitch在内核中使用的是datapath，而每个datapath必须有一个端口与之对应，ovs使用的datapath名字是ovs-system，所以系统中就冒出来一个ovs-system的网卡，没有任何用途，忽略它既可。你也根本删不掉它的。

It's not used for anything, and not useful for anything. It is mostly historical. A Linux kernel Open vSwitch datapath needs to have a port named the same as the datapath. Open vSwitch needs one datapath, and it names it ovs-system, so there's a port with the same name, even though it doesn't get used for anything.