IBM 990 7.5.6 References

Chapter 7. Sysplex functions 183
Draft Document for Review April 7, 2004 6:15 pm 6947ch07.fm
System automation - I/O operations
When using system automation, take care when using PROHIBIT or BLOCK on a port that is
participating in Dynamic Channel Path Management.
When blocking a managed channel port, configuring the CHPID OFFLINE to all members of
the LPAR Cluster is all that is required. Dynamic Channel Path Management will ensure that if
the CHPID is configured to managed subsystems, then the CHPID will be deconfigured from
all subsystems to which it is currently configured.
When blocking a port connected to a managed subsystem, the port must first be disabled for
Dynamic Channel Path Management usage. This is done using the VARY SWITCH command
to take the port OFFLINE to Dynamic Channel Path Management. This command should be
issued on all partitions that are running DCM. Disabling the port for Dynamic Channel Path
Management usage will deconfigure all managed channels which are connected to the
subsystem through that port. Once the port is disabled to Dynamic Channel Path
Management, it can then be blocked.
When prohibiting a set of ports, if any of the ports are connected to managed subsystems,
then the PROHIBIT operation must be preceded by the VARY SWITCH command(s) to
disable the managed subsystem ports to Dynamic Channel Path Management. As in the
blocking case, this will cause any managed channels currently connected to the subsystem
port(s) to be deconfigured. Once the subsystem ports are disabled to Dynamic Channel Path
Management, the PROHIBIT function can be invoked. This must then be followed by the
VARY SWITCH command(s) to re-enable the prohibited subsystem ports to Dynamic
Channel Path Management.
When ports are unprohibited or unblocked, these operations need to be followed, as
necessary, by VARY SWITCH commands to bring ports ONLINE to Dynamic Channel Path
Management.
7.5.6 References
For more detailed information on Intelligent Resource Director, see z/OS MVS Planning
Workload Management, SA22-7602, and the IBM Redbook z/OS Intelligent Resource
Director, SG24-5952.