Replacing Fabric 2 Modules with Fabric 3 Modules Technical Note

Introduction

This document describes the steps needed to replace Fabric 2 modules with Fabric 3 modules.

Prerequisites

Requirements

Cisco recommends that you have knowledge of the Cisco Nexus operating system CLI.

Components used

The information in this document is based on these software and hardware versions:

·         Fabric 3 module (Cisco NX-OS Release 8.3(1) or later)

·         Fabric 2 module

The information in this document was created from the devices in a specific lab environment. If your network is live, make sure that you understand the potential impact of any command.

Replacing Fabric 2 Modules with Fabric 3 Modules

If you are running Cisco NX-OS 8.3(1) or a later release on a Cisco Nexus 7700 Series switch, you can replace all the Fabric 2 modules with Fabric 3 modules. You can replace the modules during operations if you replace each module within a couple of minutes so that the switch can maintain its designed airflow. The replacement procedure is non-disruptive to switch operations if there is at least one fabric module installed and operating in the switch while you replace the other fabric module.

To replace Fabric 2 modules with Fabric 3 modules, follow these steps:

1. Verify that the switch is running Cisco NX-OS Release 8.3(1) or a later release.

2. Replace the Fabric 2 module that is in the lowest numbered fabric slot.

3. Enter the show module xbar command, as shown in the example below, to display the types of fabric modules installed in the fabric slots.

Example:  Listing the Fabric Module Types Installed in the Switch

switch# show module xbar

Xbar Ports  Module-Type                         Model              Status

---  -----  ----------------------------------- ------------------ ----------

1    0      Fabric Module 3                     N77-C7710-FAB-3    ok

3    0      Fabric Module 3                     N77-C7710-FAB-3    ok

5    0      Fabric Module 3                     N77-C7710-FAB-3    ok

Xbar Sw               Hw

---  ---------------  ------

1    NA               0.509

3    NA               0.509

5    NA               0.505

Xbar MAC-Address(es)                         Serial-Num

---  --------------------------------------  ----------

1    NA                                      JAE214105ZS

3    NA                                      JAE214105ZV

5    NA                                      JAE2122035C

* this terminal session

4. If one or more of the fabric modules is indicated as “Fabric Module 2,” repeat Step 2 to replace the Fabric 2 module with the Fabric 3 module and then repeat Step 3 to display the types of fabric modules installed in the fabric slots.

Recovery Procedure for Downgrading to Fabric 2 modules (if there are issues with the Fabric 3 Upgrade)

This section describes the steps needed to downgrade from Fabric 3 modules to Fabric 2 modules if there are issues with the Fabric 3 upgrade.

Scenario 1:

If both Fabric 2 and Fabric 3 modules are up in the switch (FAB2_FAB3 mode), then replace the Fabric 3 modules with the Fabric 2 modules.

Scenario 2:
If the switch is loaded with Fabric 3 modules only (FAB3 mode), then migrating to Fabric 2 is disruptive.  The Fabric 2 module will power down when the switch is in FAB3 mode.

Perform the steps given below to replace FAB3 modules with FAB2 modules when the switch is loaded with only FAB3 modules:

1. Replace one FAB3 module with a FAB2 module. The switch is still in FAB3 mode.

2.  FAB2 will be in power down state.

3. Repeat Step 1 to replace FAB3 modules with FAB2 modules in all slots. All the FAB2 modules will be in power down state.

4. The I/O modules will be powered down due to non-availability of Stage2 bandwidth.

5. Power up FAB2 modules by using the no poweroff xbar moduleNumber command.

6. After a FAB2 module is up, all the I/O modules will also power up.

7. Repeat Step 5 to power up the remaining FAB2 modules.