IOCP statements for ICP

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The RESOURCE statement is used to specify all the logical partition names defined in a machine configuration. Reserved partitions can be specified with an asterisk (*) along with their associated CSS and MIF image IDs. Space in the hardware system area (HSA) is allocated for reserved LPs, but cannot be used until a dynamic I/O configuration is made to assign a name to the LP. IOCP automatically reserves a partition for every possible CSS and MIF image ID that does not have a logical partition name specified. If you choose to specify a reserved partition, the following rules apply when specifying reserved LPs:

  • A reserved LP must have a user-specified MIF image ID
  • A reserved LP cannot have any channel paths assigned to it
  • An IOCDS cannot contain only reserved LPs. At least one LP must be defined with a name.

IOCP automatically defines enough reserved partitions to ensure that the maximum number of LPs for your z17 are available in every CSS. You do not need to define reserved partitions with the RESOURCE statement.

Dynamic CHPID Management (DCM) channel paths defined for a given LPAR cluster are shareable among all active LPs that have joined that cluster. Other than DCM channel paths, you must assign each channel path to a logical partition in an LPAR IOCDS. For each DCM channel path, ICP requires the CHPARM keyword have a value of 01 and the IOCLUSTER keyword on a CHPID statement. All other channel paths require the PART|PARTITION, NOTPART, or SHARED keyword on all CHPID statements unless a channel path is defined as spanned by specifying multiple CSS IDs in the PATH keyword of the IOCP CHPID statement.

Use the CHPARM and IOCLUSTER keywords on the CHPID statement to specify channel paths reserved for the use of a particular LPAR cluster. A DCM channel path becomes available to a candidate logical partition when the LP is activated and joins the specified cluster.

Use the CHPID PART|PARTITION, NOTPART, and SHARED keywords to determine which:
  • Channel paths are assigned to each LP
  • Devices and control units are shared among LPs
  • Channel paths are reconfigurable
  • Channel paths are shared

Use the CHPID CPATH keyword to connect two internal coupling channels.

Use the CHPID PATH keyword to define a channel path as spanned to multiple CSSs. Spanned channel paths are also shared channel paths.

DCM channel paths are implicitly shared. Use of the IOCLUSTER keyword implies a null access list (no logical partition has the channel path brought online at activation) and a candidate list of all defined logical partitions. The IOCLUSTER keyword is mutually exclusive with the PART|PARTITION and NOTPART keywords.

All LP names that you specify in the CHPID statements must match the names specified in the RESOURCE statement. An IOCDS must have at least one LP name defined.

PARTITION={(CSS(cssid),{name|0}[,REC])|
          (CSS(cssid),access list)|
          (CSS(cssid),(access list)[,(candidate list)][,REC])|
       ((CSS(cssid),(access list)[,(candidate list)]),...)}

NOTPART={(CSS(cssid),access list)|
        ((CSS(cssid),(access list)[,(candidate list)]),...)}

IOCLUSTER=cluster_name

SHARED

CPATH=(CSS(cssid),chpid number)
Where:
name
specifies the name of the LP that has authority to access the CHPID. The LP name is a 1 - 8 alphanumeric (0 - 9, A - Z) character name that must have an alphabetic first character. Special characters ($, #, @) are not allowed. A reserved LP cannot have any channel paths assigned to it.

The following words are reserved and you cannot use them as LP names:

  • PHYSICAL
  • REC
  • SYSTEM
  • PRIMnnnn (where nnnn are digits)

ICP IOCP supports a maximum of 85 LP names (models ME1 and ML1) for the CPC. For models ME2, ML2, MER, and MLR, ICP IOCP supports a maximum of 40 LP names.

cluster_name
specifies the name of an LPAR cluster that has authority to access the specified DCM CHPID. The name of the LPAR cluster is a one- to eight- alphanumeric character name (0-9, A-Z) that must have an alphabetic first character. Special characters ($, #, @) are not allowed.
REC
specifies that the CHPID is reconfigurable. A reconfigurable CHPID must have an initial access list of one LP name. Its candidate list must consist of one or more LP names.
access list
specifies the LPs that have initial access to the CHPID at the completion of the initial power-on reset. An LP name can only appear once in an access list.

You can specify that no LPs access the channel path following LP activation for the initial POR of an LPAR IOCDS. Specifying 0 indicates a null access list.

candidate list
specifies the LPs that have authority to access the CHPID. Any LP that is not in a CHPIDs candidate list cannot access the CHPID.

You can specify as many LP names as your CPC supports. However, the number of unique LP names specified in both the access list and candidate list can not exceed the number of LPs your CPC supports.

If you specify the candidate list, you do not need to specify again the LP names specified in the initial access list. The initial access list is always included in the candidate list.

An LP name can only appear once in a candidate list. If the candidate list is not specified, it defaults to all LPs in the configuration for reconfigurable and shared channels.

Note: It is highly recommended that a peer mode coupling CHPID (ICP, CS5, CL5, and CL6) have at most one coupling facility LP specified in its initial access list in order to avoid confusion on subsequent LP activations. A peer mode coupling CHPID can be online to only one coupling facility LP at a time.

Using the SHARED keyword specifies that the channel paths on the CHPID statement are shared. More than one LP, at the same time, can access a shared CHPID. When CHPIDs are not shared, only one LP can access it. Although you can dynamically move a reconfigurable CHPID between LPs, it can only be accessed by 1 LP at any given time. CVC and CBY channel paths (TYPE keyword) cannot be shared. On CF only models and ICP channel paths cannot be shared.

The CPATH keyword is required for a coupling-type CHPID (ICP, CS5, CL5, and CL6) and specifies the connection between 2 CHPIDs at either end of a coupling link. For example: 

PATH=FE,TYPE=ICP,CPATH=FF,...
PATH=FF,TYPE=ICP,CPATH=FE,...

specifies that ICP channel path FF connects to ICP channel path FE. Every ICP channel path of a coupling facility must be connected to an ICP channel path of a z/OS® LP. The connection needs to be specified for each channel path. ICP channel paths cannot connect to each other if they both have candidate lists with the same, single logical partition. This restriction prevents the definition of internal coupling channels in an PR/SM configuration with only one logical partition. Also, an ICP channel path cannot connect to itself.

The CPATH value for a ICA SR coupling link CHPID specifies the CSS and CHPID number this ICA SR coupling link CHPID connects with on the target system. For example: 
PATH=C0,TYPE=CS5,CPATH=(CSS(1),D0),...
Defines an ICA SR coupling link CHPID, C0, on this system that connects with ICA SR coupling link CHPID D0 in CSS 1 on the remote system.