IBM Z9, Planning Manual

Page: 69 / 274

Note: Because the 3990-3 supports only eight logical paths per cluster, you would
need to configure offline the channel images so that the number of logical
paths requested from each cluster remains at eight.
It is also possible to manage how logical paths are established by using IOCP or
Hardware Configuration Definition (HCD) to create I/O configuration definitions that:
v Define a subset of LPs that will have their corresponding channels configured
online at power-on reset (POR) (CHPID access list)
v
Allow LPs to configure online their channels at a later time (CHPID candidate list)
Use IOCP or HCD to define the access lists and candidate lists for channel paths to
determine the configurability of a channel to an LP. This capability exists for both
unshared and shared channels and can help automate and establish the
configuration in Figure 2-4. Additionally, HCD allows you to dynamically change the
access list and candidate list for a channel path.
LP1 LP2 LP3 LP4 LP5
CHP
30
CHP
31
CHP
32
CHP
33
3990-3
LPAR
Cluster 1 Cluster 2
Each shared ESCON
channel establishes 4
logical paths to the 3990.
For LP1, LP2, and LP3,
CHPIDs 30, 31, 32, and 33
are all configured online.
For LP4, CHPIDs 30 and
32 are configured offline.
For LP5, CHPIDs 31 and
33 are configured offline.
Figure 2-4. Configuring Offline Unneeded Channels or Shared Channels on an LP Basis
Chapter 2. Planning Considerations
2-15