Fabric OS v6.4.1 Release Notes v1.0 Page 12 of 62
FOS Migration Considerations
This section contains important details to consider before migrating to or from this FOS release.
TSBs - Critical Issues to Consider Prior to Installing This FOS Release
Technical Support Bulletins (TSBs) are produced to provide detailed information about high priority
defects or issues present in FOS releases. The following sections specify all current TSBs that have
been identified as being a risk to or resolved with this specific version of Fabric OS. Please review
carefully and refer to the complete TSB for relevant issues prior to migrating to this version of code.
TSBs can be found at http://my.brocade.com under the “Technical Documentation” section of the
TSB Issues Outstanding in FOS v6.4.1
Issues in the following list of TSBs are known to be potential risks to using FOS v6.4.1 and should be
considered carefully prior to using this release of code:
TSB Issues Resolved in FOS v6.4.1
Issues in the following list of TSBs are known FOS v6.4.x risks that are not exposures in FOS v6.4.1.
Note that the issues addressed in this list of TSBs may also be resolved in other FOS releases. Refer
to the specific Release Notes for each release to verify resolution details.
There are no TSBs currently issued for FOS v6.4 releases.
Recommended Migration Paths to FOS v6.4.1
Migrating from FOS v6.2.x
Migrating from FOS v6.2.xMigrating from FOS v6.2.x
Migrating from FOS v6.2.x
For units currently operating at FOS v6.2.x, it is recommended to use FOS v6.3.0d, 6.3.1b (or later) or
v6.3.2 prior to migrating to FOS v6.4.1.
Migrating from FOS v6.3
Migrating from FOS v6.3Migrating from FOS v6.3
Migrating from FOS v6.3.x
For units currently operating at FOS v6.3.x, there are no special steps required to migrate to FOS
FOS Upgrades and Downgrades
Non-disruptively upgrading to Fabric OS v6.4 is only allowed from Fabric OS v6.3. This policy to support only
one-level non-disruptive migration, which began with FOS v6.0.0, provides more reliable and robust migrations
for customers. By having fewer major changes in internal databases, configurations, and subsystems, the
system is able to perform the upgrade more efficiently, taking less time and ensuring a truly seamless and non-
disruptive process for the fabric. The one-release migration policy also reduces the large number of
upgrade/downgrade permutations that must be tested, allowing Brocade to spend more effort ensuring the
supported migration paths are thoroughly and completely verified.
Disruptive upgrades to Fabric OS 6.4 are allowed and supported from FOS 6.2 and 6.3 (up to a two-level