[CentOS-virt] SNMP monitoring

[Lars Hecking]

 It seems it's not possible to monitor kvm virtual image network interfaces
 via SNMP. MRTG's cfgmaker says

### The following interface is commented out because:
### * has no ifSpeed property

 and other monitors are consistently reporting that vm's interfaces are
 exceeding traffic thresholds (even on lo ...). Which is no surprise if
 the threshold is zero.

 I found a hint on some Debian forum that this behaviour is caused by the
 virtio driver. So I was wondering, is it recommended or are there advantages
 to configuring one of the emulated drivers instead (ne2k_pci,i82551,i82557b,
 i82559er,rtl8139,e1000,pcnet)? Or can I "fake it" somehow in the vm's snmpd
 config?