concept-job.rst

Asynchronous jobs

Most of storage manipulation methods, for example :ref:`CreateOrModifyVG <LMI-StorageConfigurationService-CreateOrModifyVG>`, can be time-consuming. Therefore the methods only check input parameters and return immediately with a reference to :ref:`LMI_StorageJob <LMI-StorageJob>` instance. The operation itself is performed asynchronously on the server in a separate thread.

The returned :ref:`LMI_StorageJob <LMI-StorageJob>` instance can be then used to either pull the operation status or applications can subscribe for job events and get an indication when status of a job changes.

Currently, only one job is being executed at a time, all others are enqueued and executed later.

Job status

The job status is exposed in :ref:`OperationalStatus <CIM-ManagedSystemElement-OperationalStatus>` and :ref:`JobState <CIM-ConcreteJob-JobState>` properties. Their combination compose unique job status:

Job is	OperationalStatus	JobState
Queued	Dormant	New
Suspended	OK	Suspended
Running	OK	Running
Finished OK	Completed, OK	Completed
Failed	Completed, Error	Exception
Cancelled	Stopped	Terminated

:ref:`Job.RequestStateChange <CIM-ConcreteJob-RequestStateChange>` method can be used to suspend, resume and cancel a job, while following rules apply:

• Only Queued job can be suspended.
• Only Suspended job can be resumed.
• Only Queued or Suspended job can be cancelled.

Note

Running job cannot be terminated in any way.

Job state machine.

By default, all job instances disappear automatically after 60 seconds after they reach any final state. This can be overridden by setting :ref:`TimeBeforeRemoval <CIM-ConcreteJob-TimeBeforeRemoval>` and :ref:`DeleteOnCompletion <CIM-Job-DeleteOnCompletion>` properties of a job.

Return value and output parameters

Return value and output parameters of an asynchronous method call are stored in :ref:`LMI_StorageJob.JobOutParameters <CIM-ConcreteJob-JobOutParameters>` property, which is EmbeddedObject of a class, which has property for each output parameter of the asynchronous method. The method return value itself is available there too, as __ReturnValue property.

For compatibility with SMI-S, the output parameters are also included in :ref:`LMI_StorageMethodResult.PostCallIndication <CIM-MethodResult-PostCallIndication>` property, which is associated to the job. The property itself is embedded instance of :ref:`CIM_InstMethodCall<CIM-InstMethodCall>` class. Return value is stored in its :ref:`ReturnValue <CIM-InstMethodCall-ReturnValue>` property. Output parameters are stored in its :ref:`MethodParameters <CIM-InstMethodCall-MethodParameters>` property.

:ref:`LMI_AffectedStorageJobElement<LMI-AffectedStorageJobElement>` association can be also used to find created/modified element of a :ref:`LMI_StorageJob <LMI-StorageJob>` instance.

Instance diagram of a job before finishing.

Instance diagram of a job after finishing.

Supported event filters

• PercentComplete property of a job changed:

  SELECT * FROM LMI_StorageInstModification
      WHERE SourceInstance ISA LMI_StorageJob
          AND SourceInstance.CIM_ConcreteJob::PercentComplete
              <> PreviousInstance.CIM_ConcreteJob::PercentComplete
  

• State of a job changed:

  SELECT FROM LMI_StorageInstModification
      WHERE SourceInstance ISA CIM_ConcreteJob
          AND SourceInstance.CIM_ConcreteJob::JobState <> PreviousInstance.CIM_ConcreteJob::JobState
  

• A job reaches state "Completed/OK":

  SELECT * FROM LMI_StorageInstModification
      WHERE SourceInstance ISA LMI_StorageJob
          AND SourceInstance.CIM_ConcreteJob::JobState = 7
  

• A job reaches state "Completed/Error":

  SELECT * FROM LMI_StorageInstModification
      WHERE SourceInstance ISA LMI_StorageJob
          AND SourceInstance.CIM_ConcreteJob::JobState = 10
  

• New job was created:

  SELECT * FROM LMI_StorageInstCreation WHERE SourceInstance ISA LMI_StorageJob
  

Note

All other indication filter queries will be rejected.