HP Cisco MDS 9120 Cisco MDS 9000 Family Release Notes for Cisco MDS SAN-OS Rel - Page 20

Downgrading Your Cisco MDS SAN-OS Software Image Send documentation comments to [email protected] If you are performing an upgrade on one of those switches, you should follow the nondisruptive upgrade path shown in Table 5, 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(2b) to SAN-OS Release 3.2(1a)), 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. Downgrading Your Cisco MDS SAN-OS Software Image This section lists the guidelines recommended for downgrading your Cisco MDS SAN-OS software image and contains the following sections: • General Downgrading Guidelines, page 20 • Downgrading the SSI Image on Your SSM, page 22 General Downgrading Guidelines Use the following guidelines to nondisruptively downgrade your Cisco MDS SAN-OS Release 3.2(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 CLI command to determine what you need to disable. • Layer 2 switching traffic is not disrupted when downgrading to Cisco SAN-OS Release 2.1(2) or later. • Use the show install all impact downgrade-image CLI 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 7 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. 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. - iSCSI: If you are downgrading from SAN-OS version 3.0(x) to a lower version of SAN-OS, enable iSCSI if an IPS module or a MPS-14/2 module is online in the switch. Otherwise, the downgrade will disrupt traffic. Cisco MDS 9000 Family Release Notes for Cisco MDS SAN-OS Release 3.2(1a) 20 OL-14116-02