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Monitoring Fibre Channel Interface Load Balancing

You can use operational mode commands to monitor load balancing when the switch is in FCoE-FC gateway mode:

Monitoring the Interface Load-Balancing State

Purpose

Monitor the number of sessions, whether load balancing is enabled or disabled, and the load-balancing weight for each native Fibre Channel (FC) interface.

Note:

A session is a FLOGI or FDISC login to the FC SAN fabric. Session does not refer to end-to-end storage sessions.

Action

To monitor the load-balancing state of the native FC interfaces in the CLI, enter the following CLI command:

user@switch> show fibre-channel proxy np-port

For example:

Meaning

Table 1 summarizes key output fields for the FC interface load-balancing state.

Table 1: Summary of Key FC Interface Load-Balancing Output Fields

Field

Values

Fabric

Name of the fabric.

Fabric-id

Fabric ID number.

NP-Port

NP_Port interface connected to the FCoE forwarder (FCF) or the FC switch.

State

FCID state of the NP_Port interface:

  • online—The port is online and connected to the FC switch. FCoE devices can log in to the FC switch using this port.

  • isolated—The port is isolated and is not part of the load-balancing function. FCoE devices cannot log in to the FC switch using this port.

  • offline—The port is offline.

Sessions

Number of active sessions on the NP_Port interface.

LB state

Load-balancing state:

  • On—Load balancing is on

  • Off—Load balancing is off.

LB weight

Load-balancing weight, which reflects the port speed:

  • 2—Port speed is 2 Gbps.

  • 4—Port speed is 4 Gbps.

  • 8—Port speed is 8 Gbps.

The gateway determines the least-loaded interface using the following weighted round-robin (WRR) algorithm:

(number-of-sessions * max-weight) / weight

where max-weight is an internal constant. If the load on the FC interfaces is equal, the session is assigned to the interface with the highest link speed (the greatest weight).

Monitoring the Fabric Load-Balancing Algorithm

Purpose

Monitor the type of load-balancing algorithm (simple, ENode-based, or FLOGI-based) used on the native FC interfaces, whether or not automated load rebalancing is enabled, and the load rebalancing state of the fabric.

Action

To monitor the load-balancing algorithm used on the native FC interfaces and the load rebalancing state in the CLI, enter the following CLI command:

user@switch> show fibre-channel proxy fabric-state

For example:

Meaning

You can configure each local FC fabric on an FCoE-FC gateway to use one of three types of load-balancing algorithms, simple, ENode-based, or FLOGI-based. All of the native FC interfaces (NP_Ports) in a particular gateway FC fabric use the same load-balancing algorithm (the load-balancing algorithm is applied on a per-fabric basis).

Table 2 summarizes key output fields for the FC interface load-balancing algorithm and state.

Table 2: show fibre-channel proxy fabric-state Output Fields

Field Name

Field Description

Fabric

Name of the fabric.

Fabric-id

Fabric ID number.

Proxy load balance algorithm

Load-balancing algorithm used on the FCoE-FC gateway FC fabric:

  • Simple—Load balancing is based on the weighted utilization (load) of the NP_Ports connected to an FC fabric. Each new FLOGI or FDISC is assigned to the least-loaded link.

    On a link load rebalance, only the sessions that need to be moved to another link are logged out. When those sessions log in again, they are placed on active NP_Port interfaces in a balanced manner.

  • ENode-based—Load balancing is based on the ENode FLOGI. When an ENode logs in to the fabric, all subsequent FDISC sessions (VN_Port sessions) associated with that ENode are placed on the same link as the ENode FLOGI session, regardless of the link load. New ENode FLOGIs are placed on the least-loaded link.

    On a link load rebalance, all sessions are logged out. When the sessions log in again, they are placed on active NP_Port interfaces in a balanced manner.

  • FLOGI-based—Load balancing is based on the ENode FLOGI. When an ENode logs in to the fabric, all subsequent FDISC sessions (VN_Port sessions) associated with that ENode are placed on the same link as the ENode FLOGI session, regardless of the link load. New ENode FLOGIs are placed on the least-loaded link.

    On a link load rebalance, only the sessions that need to be moved to another link are logged out. When those sessions log in again, they are placed on active NP_Port interfaces in a balanced manner.

Fabric WWN verification

Fabric worldwide name (WWN) verification check state on the FCoE-FC gateway fabric:

  • Yes—Fabric WWN verification check is enabled.

  • No—Fabric WWN verification check is disabled.

Auto load rebalance enabled

Automated link load rebalancing configuration for the FCoE-FC gateway fabric:

  • No—Automated load balancing is disabled (default state).

  • Yes—Automated load balancing is enabled.

Last rebalance start-time

Time that the last link load rebalance began on the FCoE-FC gateway fabric:

  • Never—The link load has never been rebalanced.

  • Timestamp value—Time the last link load rebalancing started.

Last rebalance end-time

Time that the last link load rebalance ended on the FCoE-FC gateway fabric:

  • Never—The link load has never been rebalanced.

  • Timestamp value—Time the last link load rebalancing ended.

Last rebalance trigger

Event that triggered the last link load rebalance on the FCoE-FC gateway fabric:

  • None—The link load has never been rebalanced.

  • Config-CLI—Configure (enable) automated load balancing.

  • Request-CLI—Rebalance requested from the CLI using the request fibre-channel proxy load-rebalance fabric fabric-name operational command.

  • Preview-CLI—Rebalancing dry run requested from the CLI using the request fibre-channel proxy load-rebalance dry-run fabric fabric-name operational command. Indicates that the switch completed the dry run. A dry run simulates a link load rebalance and displays a list of sessions that might be affected if you request an actual rebalance.

  • Link-up—New FC link (NP_Port) up on the FCoE-FC gateway fabric, which causes a rebalance to distribute sessions to the new link.

  • Restore-complete—If the FC process on the switch restarts, the switch attempts to restore the session state that existed before the restart. When automated rebalance is enabled, restore-complete indicates that the sessions have been restored and rebalanced.

Last rebalance trigger-time

Time that the last link load rebalance was triggered on the FCoE-FC gateway fabric:

  • Never—Link load rebalancing has never been triggered.

  • Timestamp value—Time the last link load rebalancing was triggered.

Last rebalance trigger-result

Result of the last trigger event on the FCoE-FC gateway fabric:

  • Never—Link load rebalancing has never been triggered.

  • Not-configured—Automated rebalancing is not configured on the FCoE-FC gateway fabric.

  • Not-required—Last rebalance trigger did not require rebalancing the link load (the link load was already balanced across the active NP_Port links).

  • In-progress—Link load rebalancing is in progress and has not finished yet.

  • Restore-in-progress—The switch is recovering from an FC process restart and is in the process of restoring the sessions to the active NP_Port links.

  • Success—Link load rebalancing was successful.

  • Logged-out-all—All sessions have been logged out.

  • Preview-complete—The switch has finished simulating a dry run rebalancing request from the CLI (request fibre-channel proxy load-rebalance dry-run fabric fabric-name operational command) and reported the sessions that might be affected if you request an actual link load rebalance.

  • Fabric-deletion-in-progress—FCoE-FC gateway fabric is in the process of being deleted.

Note:

A trigger event does not necessarily result in a rebalance action. Link load rebalancing only occurs if the NP_Port interface session load is not balanced at the time of the trigger event.

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