IBM z13s Technical Manual page 389

Previous firmware updates, which require an initial machine load (IML) of the z13s server
to be activated, can block the ability to run a concurrent driver upgrade.
An icon on the Support Element (SE) allows you or your IBM service support
representative (SSR) to define the concurrent driver upgrade sync point to be used for an
EDM.
The ability to concurrently install and activate a driver can eliminate or reduce a planned
outage.
z13s servers introduce concurrent driver upgrade (CDU) cloning support to other CPCs for
CDU preinstallation and activation.
Concurrent crossover from Driver level N to Driver level N+1, and to Driver level N+2, must
be done serially. No composite moves are allowed.
Disruptive upgrades are permitted at any time, and allow for a composite upgrade (Driver
N to Driver N+2).
Concurrently backing up to the previous driver level is not possible. The driver level must
move forward to driver level N+1 after EDM is initiated. Unrecoverable errors during an
update can require a scheduled outage to recover.
The EDM function does not eliminate the need for planned outages for driver-level upgrades.
Upgrades might require a system level or a functional element scheduled outage to activate
the new LIC. The following circumstances require a scheduled outage:
Specific complex code changes might dictate a disruptive driver upgrade. You are alerted
in advance so that you can plan for the following changes:
– Design data or hardware initialization data fixes
– CFCC release level change
OSA channel-path identifier (CHPID) code changes might require physical channel ID
(PCHID) Vary OFF/ON to activate new code.
Crypto CHPID code changes might require PCHID Vary OFF/ON to activate new code.
Note: zUDX clients should contact their UDX provider before installation of MCLs. Any
changes to Segment 2 or 3 from a previous MCL level might require a change to the
client's UDX. Attempting to install an incompatible UDX at this level will result in a Crypto
checkstop
Changes to the code of native PCIe features might require extra action from the client if
the specific feature must be offline to the connecting LPARs before the new code can be
applied and brought back online later.
In changes to the Resource Group (RG) code, all native PCIe features within that RG
might need to be varied offline to all connection LPARs by the client and back online after
the code is applied.
z13s servers continue to support to activate MCLs concurrently on various channel types
Chapter 9. Reliability, availability, and serviceability
361