On the SG300-52, I've noticed that SNMP monitoring of LAGs versus regular switch ports give incorrect (way too large and unrealistic) values for the octets transferred.
For simplicities sake, let's say I have two devices connected a SG300-52 switch. One of these devices is using LAG (802.3ad) with GigE ports while one is not (vanilla GigE). Transferring data from device 2 (non-LAG) to device 1 (LAG) shows an average rate of ~80MB/s on device 2 and device 1 using software interface monitoring tools. Monitoring SNMP ifOutOctets the LAG port for device 1 shows an average bandwidth (so the derivative of the raw SNMP value) of ~320MB/s. Looking at ifInOctets for the non-LAG device 2 port shows an average bandwidth of ~80MB/s.
Even ignoring the implausibly large value for bandwidth of the LAG device, communication to this device is only from the non-LAG device, i.e. there aren't other devices on this switch that are communicating with the LAG device at the same time as this test.
Using ifHC*Octets yields even more ridiculous results for the LAG group, while non-LAG ports still report bandwidth correctly. Has anyone else come across this?