Service Manual

Fabric OS 7.4.0a Release Notes v2.0 Page 25 of 53
FOS Migration Considerations
This section contains important details to consider before migrating to or from this FOS release.
FOS Upgrade and Downgrade Special Considerations
DCX/DCX-4S/DCX8510-8 units with FCOE10-24 blades running any FOS v7.3.x can be non-disruptively
upgraded to FOS v7.4.0a. This upgrade is non-disruptive to both FC and FCoE traffic (when using FCOE10-24
blades). In FOS versions prior to v7.1.0, firmware upgrade is disruptive to FCoE traffic.
Any firmware activation on Brocade 7800, or DCX, DCX-4S, DCX 8510-8, DCX 8510-4 with FX8-24 will disrupt
I/O traffic on the FCIP links.
For FCIP, the best practice is to always operate the switch or blade at both ends of the tunnel with the same
level of Fabric OS, down to the maintenance release. Fabric OS upgrades should be done on both ends of the
FCIP tunnel concurrently.
Firmware downgrade from FOS v7.4 to FOS v7.3.0c or earlier verisons on Brocade 7840 should be avoided.
Otherwise, the Brocade 7840 may become faulty. (Downgrading to FOS v7.3.0b5 can be used as a
workaround.)
Disruptive
DisruptiveDisruptive
Disruptive upgrades to Fabric OS v7.4.0a are allowed and supported from FOS v7.2.x (up to a two-level
migration) using the optional “-s” parameter with the firmwaredownload command.
If there are multiple node EGs (encryption groups) in a fabric, please complete firmwaredownload on one node
at a time before downloading on another node.
Recommended Migration Paths to FOS v7.4.0a
Migrating from FOS v7.3
• Any 8G or 16G platform running any FOS v7.3.x firmware can be non-disruptively upgraded to FOS v7.4.0a.
Migrating from FOS v7.2
• Any 8G or 16G platform operating at FOS v7.2.x must be upgraded to FOS v7.3.x before non-disruptively
upgrading to FOS v7.4.0a.
• Disruptive upgrade to FOS v7.4.0a from FOS v7.2 is supported.
• Firmware clean install to FOS v7.4.0a from FOS v6.4 or later without retaining any configuration is
supported.