Disruptive Load Balancing
In Release 4.0(0)N1(2a) and later software releases, NPV supports disruptive load balancing. When disruptive
load balancing is enabled, NPV redistributes the server interfaces across all available NP uplinks when a new
NP uplink becomes operational. To move a server interface from one NP uplink to another NP uplink, NPV
forces reinitialization of the server interface so that the server performs a new login to the core switch.
Only server interfaces that are moved to a different uplink are reinitialized. A system message is generated
for each server interface that is moved.
Redistributing a server interface causes traffic disruption to the attached end devices.
Note
To avoid disruption of server traffic, you should enable this feature only after adding a new NP uplink, and
then disable it again after the server interfaces have been redistributed.
If disruptive load balancing is not enabled, you can manually reinitialize some or all of the server interfaces
to distribute server traffic to new NP uplink interfaces.
NPV Traffic Management Guidelines
When deploying NPV traffic management, follow these guidelines:
•
Use NPV traffic management only when automatic traffic engineering does not meet your network
requirements.
•
You do not need to configure traffic maps for all server interfaces. By default, NPV will use automatic
traffic management.
•
Server interfaces configured to use a set of NP uplink interfaces cannot use any other available NP uplink
interfaces, even if none of the configured interfaces are available.
•
When disruptive load balancing is enabled, a server interface may be moved from one NP uplink to
another NP uplink. Moving between NP uplink interfaces requires NPV to relogin to the core switch,
causing traffic disruption.
•
To link a set of servers to a specific core switch, associate the server interfaces with a set of NP uplink
interfaces that all connect to that core switch.
•
Configure Persistent FC IDs on the core switch and use the Traffic Map feature to direct server interface
traffic onto NP uplinks that all connect to the associated core switch.
NPV Guidelines and Limitations
When configuring NPV, note the following guidelines and limitations:
•
In-order data delivery is not required in NPV mode because the exchange between two end devices
always takes the same uplink from the edge switch to the core. Upstream of the edge switch, core switches
will enforce in-order delivery if configured.
•
You can configure zoning for end devices that are connected to edge switches using all available member
types on the core switch. For fWWN, sWWN, domain, or port-based zoning, use the fWWN, sWWN,
domain, or port of the core switch in the configuration commands.
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Configuring N Port Virtualization
NPV Guidelines and Limitations
