PowerEdge: Common Network Partition and Teaming Mode mistake that result in unexpected issues
Summary: What is a common Network Partition and Teaming Mode mistake that may result in unexpected network issues.
Symptoms
Q2: Is it supported by Dell EMC?
Cause
Resolution
Answers:
With Dell EMC BCM 578xx CNA adapters, for example, enabling NPAR or Network Partitioning allows for eight partitions (logical NICs) that may be presented to the Host (Server) Operating System. With a four-port adapter, each physical port contains two partitions (logical NICs) that combined share the physical capabilities of that single port. With a two-port adapter, each physical port contains four partitions (logical NICs) that combined share the physical capabilities of that single port.
A common misconception is that these eight partitions are equivalent to eight physical ports which is not the case. Care must be taken when configuring these partitions so as not to overload a single physical port and not to combine multiple partitions from the same physical port into the same team or virtual switch.
Regardless of the Operating System, Dell EMC Engineering DOES NOT support an NPAR configuration where a team or virtual switch (simple or distributed) or logical network switch (N-VDS) contains more than one partition from the same physical port.
Not only are multiple partitions from the same physical port not supported in a team or virtual switch, that configuration does not provide any physical redundancy, adds additional driver stack overhead, adds complexity, and may result in various unexpected network issues. These unexpected issues could be things like:
- Performance issues
- Port flapping or network disconnects
- NetQ or Mac filter errors in the OS logs
- With virtualization Operating Systems, you may encounter errors attempting to move virtual machines from one host to a second.
- Replication of ingress traffic across partitions from the same physical port
Now the documentation includes a chapter about Feature Constraints that lists what is supported or not on some features:
https://dl.dell.com/FOLDER07785443M/1/QLogic_QC_E4_Manual_External_End_User_35.30.00.09.zip
From UsersGuide_Dell_41000_Series_Adapters_AH0054602-00Z.pdf: page 358
This article is updated as new information becomes available.