HP StorageWorks XPath OS 7.4.X Command Reference Guide (AA-RVHCC-TE, September 2005)

68 XPath OS CLI commands
Turns on the dynamic load sharing option.
Synopsis
dlsset
Availability
admin
Description
Use this command to allow load sharing when a fabric change occurs.
Routing is done on a per-source-port basis. This means that all the traffic coming in from a port (either
E_Port or Fx_Port) directed to the same remote domain is routed through the same output E_Port.
To optimize fabric utilization, when there are multiple equivalent paths to a remote MP Router, traffic is
shared among all the paths. Load sharing occurs when a MP Router reboots. In addition, if dynamic load
sharing is enabled, the optimal load sharing algorithm is recomputed every time a change in the fabric
occurs (an E_Port or an Nx_Port goes up or down).
A dynamic load sharing algorithm considers the link capability of the E_Ports and the Nx_Ports when
assigning routes. For example, the algorithm attempts to assign a 2-Gb/s Nx_Port to a 2-Gb/s E_Port (if
available) instead of to a 1-Gb/s E_Port.
If dynamic load sharing is turned off, load sharing is performed only at boot time, when an Nx_Port
comes up, or when a new interswitch link (ISL) comes up. Optimal load sharing is rarely achieved with this
setting.
Dynamic load sharing is turned on by default.
Notes
When dynamic load sharing is enabled, routing changes might affect working ports. For example, if an
Fx_Port goes down, another Fx_Port might be rerouted from one E_Port to a different E_Port. The MP Router
minimizes the number of routing changes, but some are necessary to achieve optimal load sharing. These
changes might affect the application, especially if the in-order delivery option is set. With the in-order
delivery option (see iodSet), routes are briefly not available (for a few seconds) after a fabric change. In
addition, some frame loss might occur. No frame loss occurs if in-order delivery is off, but there is still a
short period of time when traffic is not forwarded. This period of time is significantly shorter than when
in-order delivery is on and is usually less than 1 second.
Trunking overrides the dynamic load sharing setting.
Operands
none
Examples
To turn on dynamic load sharing:
dlsSet
switch:admin> dlsset
DLS feature enabled