Install coexistence and fallback PTFs

Description: Coexistence and fallback PTFs installed on pre-z/OS V2R1 systems allow those systems to coexist with z/OS V2R1 systems during your migration, and allow backout from z/OS V2R1 to the previous systems if necessary. Coexistence and fallback are important because they allow you to migrate systems in a multisystem configuration to z/OS V2R1 using rolling IPLs (one system at a time), allowing for continuous application availability.

Element or feature:

Multiple.

When change was introduced:

General migration action not tied to a specific release.

Applies to migration from:

z/OS V1R13 and z/OS V1R12.

Timing:

Before installing z/OS V2R1.

Is the migration action required?

Yes.

Target system hardware requirements:

None.

Target system software requirements:

None.

Other system (coexistence or fallback) requirements:

Install the appropriate PTFs.

Restrictions:

None.

System impacts:

None.

Related IBM® Health Checker for z/OS® check:

None.

Steps to take: Before introducing z/OS V2R1 into your environment, install coexistence and fallback PTFs on all pre-z/OS V2R1 systems with which your z/OS V2R1 system will coexist.

Use the SMP/E REPORT MISSINGFIX command in conjunction with the FIXCAT type of HOLDDATA as follows:

Acquire and RECEIVE the latest HOLDDATA onto your pre-z/OS V2R1 systems. Use your normal service acquisition portals or download the HOLDDATA directly from http://service.software.ibm.com/holdata/390holddata.html. Ensure that you select Full from the Download NOW column to receive the FIXCAT HOLDDATA, as the other files do not contain FIXCATs.
Run the SMP/E REPORT MISSINGFIX command on your pre-z/OS V2R1 systems and specify a Fix Category (FIXCAT) value of "IBM.Coexistence.z/OS.V2R1". The report will identify any missing coexistence and fallback PTFs for that system. For complete information about the REPORT MISSINGFIX command, see SMP/E for z/OS Commands.
Periodically, you might want to acquire the latest HOLDDATA and rerun the REPORT MISSINGFIX command to find out if there are any new coexistence and fallback PTFs.

Reference information: For an explanation of the z/OS coexistence-migration-fallback policy, see the coexistence and fallback topic in z/OS Planning for Installation.