Cisco MDS 9000 Family Release Notes for Cisco MDS NX-OS Release 4.2(1a) (OL-19964-02, September 2009)

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Cisco MDS 9000 Family Release Notes for Cisco MDS NX-OS Release 4.2(1a)
OL-19964-02
Downgrading Your Cisco MDS SAN-OS Software Image
Performing a Disruptive Upgrade on a Single Supervisor MDS Family Switch
Cisco MDS SAN-OS software upgrades are disruptive on the Cisco MDS 9216i switch, which has a
single supervisor. If you are performing an upgrade on this switch, you should follow the nondisruptive
upgrade path shown in Table 8, even though the upgrade is disruptive. Following the nondisruptive
upgrade path ensures that the binary startup configuration remains intact.
If you do not follow the upgrade path, (for example, you upgrade directly from SAN-OS Release 2.1(2)
or earlier version to NX-OS Release 4.2(x)), the binary startup configuration is deleted because it is not
compatible with the new image, and the ASCII startup configuration file is applied when the switch
comes up with the new upgraded image. When the ASCII startup configuration file is applied, there may
be errors. Because of this, we recommend that you follow the nondisruptive upgrade path.
Note You cannot upgrade an MDS 9120 switch or an MDS 9140 switch to Cisco NX-OS 4.x. See Table 2 for
the list of switches that support Cisco NX-OS 4.x.
Resetting SNMP Notifications Following an Upgrade
The SNMP notification configuration resets to the default settings when you upgrade to Cisco NX-OS
Release 4.2(1a). Use the snmp-server enable traps command to reenable your required SNMP
notifications.
Downgrading Your Cisco MDS SAN-OS Software Image
This section lists the guidelines recommended for downgrading your Cisco MDS SAN-OS software
image and includes the following topics:
• General Downgrading Guidelines, page 23
• Downgrading the SSI Image on Your SSM, page 27
General Downgrading Guidelines
Use the following guidelines to nondisruptively downgrade your Cisco MDS NX-OS Release 4.2(1a):
• Install and configure dual supervisor modules.
• Issue the system no acl-adjacency-sharing execute command to disable acl adjacency usage on
Generation 2 and Generation 1 modules. If this command fails, reduce the number of zones, IVR
zones, TE ports, or a combination of these in the system and issue the command again.
• 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
Table 11 for the nondisruptive downgrade path for all SAN-OS releases.