Cisco Cisco MDS 9000 NX-OS Software Release 4.2

Disable all features not supported by the downgrade release. Use the show incompatibility system 
downgrade-image command to determine what you need to disable. 

Use the show install all impact downgrade-image command to determine if your downgrade will 
be nondisruptive. 

Be aware that some features impact whether a downgrade is disruptive or nondisruptive:

Fibre Channel Ports: Traffic on Fibre Channel ports can be nondisruptively downgraded. See 

 for the nondisruptive downgrade path for all SAN-OS releases.

SSM: Intelligent services traffic on the SSM, such as SANTap, NASB, and FC write 
acceleration, is disrupted during a downgrade. SSM Fibre Channel traffic is not.

Gigabit Ethernet Ports: Traffic on Gigabit Ethernet ports is disrupted during a downgrade. 
This includes IPS modules and the Gigabit Ethernet ports on the MPS-14/2 module, the 
MSM-18/4 module, and the MDS 9222i switch. Those nodes that are members of VSANs 
traversing an FCIP ISL are impacted, and a fabric reconfiguration occurs. iSCSI initiators 
connected to the Gigabit Ethernet ports lose connectivity to iSCSI targets while the downgrade 
is in progress.

IVR: With IVR enabled, you must follow additional steps if you are downgrading from Cisco 
SAN-OS Release 2.1.(1a), 2.1(1b), or 2.1.(2a). See the 

 for these instructions.

FICON: If you have FICON enabled, the downgrade path is different. See the 

.

A downgrade from NX-OS Release 4.2(3a) to SAN-OS Release 3.3(1x) is not supported on MDS 
switches, when FC-Redirect based applications, such as Data Mobility Manager or Storage Media 
Encryption, are configured in the fabric if either of the following conditions are satisfied:

A target for which FC-Redirect is configured is connected locally and there are Generation 1 
modules with ISLs configured in the switch.

A host, for which FC-redirect is configured, is connected locally on a Generation 1 module.

If these conditions exist, remove the application configuration for these targets and hosts before 
proceeding with the downgrade.

Use 

 to determine the nondisruptive downgrade path from Cisco NX-OS Release 4.2(1b). Find 

the SAN-OS image you want to downgrade to in the To SAN-OS Release column of the table and use 
the path recommended. 

The software downgrade information in 

 applies only to Fibre Channel switching traffic. 

Downgrading system software disrupts IP and SSM intelligent services traffic.

All 4.2(x) and 4.1(x) 
releases

Downgrade to NX-OS Release 4.2(x) or 4.1(x).