Aptpolicy – Brocade Fabric OS Command Reference (Supporting Fabric OS v7.3.0) User Manual

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Fabric OS Command Reference

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aptPolicy

Changes or displays the Advanced Performance Tuning (APT) policy.

SYNOPSIS

aptpolicy [policy]

DESCRIPTION

Use this command to display and change the advanced performance tuning (APT) policies on a switch.

Distributed path selection (DPS) is supported in logical fabrics. APT policy settings affecting the DPS
behavior can be configured per logical switch, and settings apply to the partition for which they are set.
Note that policy settings for the base switch or any switch in the base fabric affect all traffic going through
the base fabric including any logical fabric traffic that uses the base fabric.

When invoked without arguments, this command displays the APT policies supported on this switch, as
well as the current policy.

NOTES

You must disable the switch before using this command to change the current policy. Changes take effect
immediately for all EX/VEX_Ports after the switch is re-enabled.

For details on performance tuning, refer to the Fabric OS Administrator's Guide.

The execution of this command is subject to Virtual Fabric or Admin Domain restrictions that may be in
place. Refer to Chapter 1, "Using Fabric OS Commands" and Appendix A, "Command Availability" for
details.

OPERANDS

This command has the following operands:

policy

Specifies the APT policy. The following polices are supported:

Port-based routing policy. With this policy, the path chosen for an ingress frame is
based on both of the following items:

•

The ingress port on which the frame was received.

•

The destination domain for the frame.

The chosen path remains the same if Dynamic Load Sharing (DLS) is not
enabled. If DLS is enabled, a different path may be chosen for a fabric event.
Refer to dlsSet for a definition of a fabric event.

This policy may provide better ISL utilization when there is little or no
oversubscription of the ISLs.

Note that static routes are supported only with this policy.

Device Based Routing Policy. Device-based routing is supported in FICON
environments, and in open environments only when FICON coexists. With this
policy, the path chosen for an ingress frame is based on the following items:

•

The ingress port on which the frame was received.

•

The FC address of the source fabric device (SID) for this frame.

•

The FC address of the destination fabric device (DID) for this frame.

This policy optimizes the utilization of the available paths by allowing I/O traffic
between different source fabric device (SID) or destination fabric device (DID)
pairs to use different paths. As a result, every distinct flow in the fabric can take a
different path through the fabric. Effectively, device based routing works the same
as exchange-based routing but does not use the Originator Exchange ID (OXID)
field. This helps to ensure that the exchanges between a pair of devices stay in
order.