Monitoring special resources through RODM
You can use the Resource Object Data Manager to track the status of real resources used by Tivoli Workload Scheduler for z/OS operations. RODM is a data cache that contains information about real resources at your installation. Products such as AOC/MVS report actual resource status to RODM; RODM reflects the status by updating values of fields in classes or objects that represent the real resources. Subsystems on the same z/OS image as RODM can subscribe to RODM fields. When RODM updates a field, all subscribers to the field are notified.
IBM Tivoli Workload Scheduler for z/OS support for RODM lets you subscribe to RODM fields for fields in special resources. When RODM notifies a change, IBM Tivoli Workload Scheduler for z/OS updates resource fields that have a subscription to RODM. You can subscribe to RODM for these fields:
- AVAILABLE
- The Available field in the resource. This value overrides the default and interval values.
- QUANTITY
- The Quantity field in the resource. This value overrides the default and interval values.
- DEVIATION
- The Deviation field. You use this field to make a temporary adjustment to quantity. IBM Tivoli Workload Scheduler for z/OS adds quantity and deviation together to decide the amount that operations can allocate. For example, if quantity is 10 and deviation is -3, operations can allocate up to 7 of the resource.
You specify these keywords to invoke monitoring through RODM:
- RODMTASK
- Is specified on the OPCOPTS statement for the controller and for each tracker that communicates with a RODM subsystem.
- RODMPARM
- Is specified on the OPCOPTS statement for the controller and identifies the member of the parameter library that contains RODMOPTS statements.
- RODMOPTS
- Is specified for a controller and contains destination and subscription information.
A RODMOPTS statement is required for each field in every resource that you want to monitor. Each statement is used to subscribe to a field in a RODM class or RODM object for a field in a special resource. The RODM field value is used to set the value of the resource field.
RODMOPTS statements are read when the controller is started. When a tracker that communicates with RODM is started, it requests parameters from the controller. The controller sends subscription information to the tracker, which then subscribes to RODM. An event is created when RODM returns a value, which is used to update the special resource field in the current plan. IBM Tivoli Workload Scheduler for z/OS does not schedule operations that use a special resource until RODM has returned the current field value and IBM Tivoli Workload Scheduler for z/OS has updated the resource.
To use RODM monitoring you must ensure that:
- A tracker is started on the same z/OS image as the RODM subsystem that requests are sent to, and RODMTASK(YES) is specified for both the tracker and the controller.
- An event writer is started in the IBM Tivoli Workload Scheduler for z/OS address space that communicates with RODM. This address space creates resource events (type S) from RODM notifications, which IBM Tivoli Workload Scheduler for z/OS uses to update the current plan.
- The controller is connected to the tracker through XCF, NCF, or a submit/release data set.
- Each address space has a unique RACF® user ID if more than 1 IBM Tivoli Workload Scheduler for z/OS address space communicates with a RODM subsystem, such as when you start production and test systems that subscribe to the same RODM subsystem.
IBM Tivoli Workload Scheduler for z/OS does not load or maintain data models in the RODM cache, or require a specific data model. You need not write programs or methods to use RODM through IBM Tivoli Workload Scheduler for z/OS, or define specific objects or fields in RODM. IBM Tivoli Workload Scheduler for z/OS does not update RODM-defined data.
RODM fields have several subfields. The RODM field that IBM Tivoli Workload Scheduler for z/OS subscribes to must have a notify subfield. Through a subscription to this subfield, RODM notifies IBM Tivoli Workload Scheduler for z/OS of changes to the value subfield. IBM Tivoli Workload Scheduler for z/OS uses changes to the value subfield to monitor special resources. But only these data types are valid for IBM Tivoli Workload Scheduler for z/OS RODM support:
| Abstract data type | Data type ID |
|---|---|
| CharVar (Char) | 4 |
| Integer (Bin 31) | 10 |
| Smallint (Bin 15) | 21 |
IBM Tivoli Workload Scheduler for z/OS maintains a RODM status for all special resources in the current plan. You can check the current status in the Special Resource Monitor dialog. Each special resource has one of these values:
- N
- Not monitored. The special resource is not monitored through RODM.
- I
- Inactive. Monitoring is not currently active. IBM Tivoli Workload Scheduler for z/OS sets this status for all subscriptions to a RODM subsystem that the controller cannot communicate with. This can occur when communication is lost with RODM or with the tracker. The controller sets the value of each monitored field according to the RODMLOST keyword of RODMOPTS.
- P
- Pending. IBM Tivoli Workload Scheduler for z/OS has sent a subscription request to RODM, but RODM has not returned a value.
- A
- Active. IBM Tivoli Workload Scheduler for z/OS has received a value from RODM and the special resource field has been updated.
- The names of RODM classes, objects, and fields are case-sensitive. Ensure you preserve the case when specifying RODMOPTS statements in the parameter library. Also, if a name contains anything other than alphanumeric or national characters, you must enclose the name in quotation marks.
- If IBM Tivoli Workload Scheduler for z/OS subscribes to RODM for a resource that does not exist in the current plan and the DYNAMICADD keyword of RESOPTS has the value YES or EVENT, the event created from the data returned by RODM causes a dynamic add of the resource. DYNAMICADD is described on page ***.
- If a request from IBM Tivoli Workload Scheduler for z/OS cannot be processed immediately because, for example, long-running programs in RODM access the same data that IBM Tivoli Workload Scheduler for z/OS requests need access to, be aware of possible delays to operation start times.