Strange Speed issue with Server 2012 Team / Hyper V virtual Networks
Posted on 2014-09-22
Trying to understand what is happening and why it's happening. Basically, I am getting great file transfer speeds from 1gb nics most of the time but then get terrible speed other times. First some background:
I have 3 Dell R620 in a Hyper V / Failover cluster. Each node has the same broadcom 4 x 1gb nic setup in it with current drivers. All run server 2012r2 DC
--2 nic ports are teamed together with built in nic teaming. They have a 10.1.10.x address.
--A separate nic port on each server is just a single port with a 192.168.1.x address
--The nic team and single port go to different switches but those switches are on the same network, just separated by VLAN's. All switches are 1gb ciscos
--The nic team and the static port are then assigned to virtual nics for hyper V guests to use. Both virtual nics allow management access
1st strange thing - When both the Nic Team and stand alone ports are all connected, I try to transfer a single 2gb file from one machines c drive to another machines c drive. The file copies at 220mb/s and I can see that both virtual nic's are using their 1gb connection. But how / why is the single file getting split across two network connections and 2 vlans? The speed is normal and makes sense but how are packets split and recombined?
2nd issue - If I disable the single port network connection, forcing all traffic over the team, then the same file copy drops to 36mb/s. I can't seem to figure out why the speed is so slow.
If I disable the nic team and force the traffic over the single 1gb port, then the file copy works at 110mb/s. I guess this is actually normal and seems to be the only time that traffic flows as I would expect it to.
Any insight here? - Thanks