IBM Z9, Planning Manual

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Channel paths that are specified as shared can be accessed by one or more LPs at
the same time. Unshared channel paths that are defined to a LP as not
reconfigurable are dedicated to that LP.
ESA/390 Logical Partitions
Channel paths assigned in the IOCDS to ESA/390 LPs can be shared,
reconfigurable, or dedicated.
Coupling Facility Logical Partitions
Channel paths (CFP, CBP, CIB, and ICP) assigned in the IOCDS to coupling facility
LPs can be online to only one coupling facility at a time. On System z9 models a
coupling facility can be assigned CBP, CFP, CIB, or ICP channel paths.
Note: CBP, CFP, and ICP channel paths that are online to a single coupling facility
are shareable by multiple noncoupling facility logical partitions.
Channel Path Reconfiguration and Logical Partition Activation
When a Configure on task or an equivalent system control program command is run
successfully for a channel path in an active LP, the channel path is configured to
the LP at that time.
When a successful Configure on task completes for a channel path in an LP that is
not active , the channel path is not actually configured online to the LP at that time.
Rather, the channel path is targeted to be configured online to that LP when the LP
is activated.
When an LP is deactivated, all shared channel paths configured to it at the time of
deactivation are targeted to be configured online to it when it is subsequently
activated. Unshared channels that were last configured to this LP and were not yet
reconfigured to another LP are also targeted to be configured online to this LP at its
next activation. However, the targeting of a channel path may change prior to the
next activation due to channel reconfiguration commands, dynamic I/O configuration
changes, or POR.
Channel paths can also be targeted to be configured online to an LP by using
dynamic I/O configuration. See “Dynamic I/O Configuration Effects on Channel Path
Reconfiguration” for more details.
LPAR manages lists of targeted channel paths for each LP on an IOCDS basis so
that all channel paths that are targeted to be configured online to an LP will be
automatically configured online when that LP is activated. Exceptions to this rule
are:
v
Targeted CBP, CFP, CIB, and ICP channel paths online to another coupling
facility are not automatically configured online when that LP is activated.
Note: CBP, CFP, CIB, and ICP channel paths can only be online to one active
coupling facility LP at a time. If such a channel path is targeted to a
coupling facility LP but is already online to another coupling facility LP,
then it will be removed (deconfigured) from the activating LP.
v The targeted channel path is in single channel service mode or otherwise broken.
Dynamic I/O Configuration Effects on Channel Path
Reconfiguration
If a channel path is dynamically added to the configuration using dynamic I/O
configuration, all the LPs in the channel path access list (for a shared channel path)
or the one LP in the channel path access list (for an unshared channel path) are
Chapter 3. Determining the Characteristics of Logical Partitions
3-53
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