What is a common Network Partition and Teaming Mode mistake that may result in unexpected network issues
Summary: What is a common Network Partition and Teaming Mode mistake that may result in unexpected network issues
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Symptoms
Q1: What is a common Network Partition and Team Mode configuration mistake that may cause unexpected network issues?
Q2: Is it supported by Dell EMC?
Q2: Is it supported by Dell EMC?
Cause
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.
Resolution
Answers:
With Dell EMC BCM 578xx CNA adapters for example, enabling NPAR or Network Partitioning allows for a total of 8 partitions (logical NICs) that may be presented to the Host (Server) Operating System. With a four port adapter, each physical port will contain two partitions (logical NICs) that combined share the physical capabilities of that single port. With a two port adapter, each physical port will contain 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 as well as 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 a variety of unexpected network issues. These unexpected issues could be things like:
NOTE: This may not be a complete list of unexpected network issues. As, Dell EMC does not test unsupported configurations that include multiple partitions from the same physical port.
With Dell EMC BCM 578xx CNA adapters for example, enabling NPAR or Network Partitioning allows for a total of 8 partitions (logical NICs) that may be presented to the Host (Server) Operating System. With a four port adapter, each physical port will contain two partitions (logical NICs) that combined share the physical capabilities of that single port. With a two port adapter, each physical port will contain 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 as well as 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 a variety of 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
NOTE: This may not be a complete list of unexpected network issues. As, Dell EMC does not test unsupported configurations that include multiple partitions from the same physical port.
Now the documentation include a chapter about Feature Constraints that list 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 will be updated as new information becomes available.
Affected Products
PowerEdge, Operating Systems, Emulex Family of Adapters, Microsoft Windows Server 2016, Microsoft Windows Server 2019, Microsoft Windows 2008 Server R2, Microsoft Windows 2012 Server, Microsoft Windows 2012 Server R2, QLogic Family of Adapters
, VMware ESXi 6.5.X, VMware ESXi 6.7.X
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