Creating a new storage volume

In the Common Information Model (CIM) agent for the system, the IBMTSSVC_StorageConfigurationService class provides all the methods that are required for creating, modifying, and deleting an IBMTSSVC_StorageVolume instance. This class creates the standard volume; it also creates a thin-provisioning volume by using one of two methods: IBM extension parameters, or the Storage Management Initiative – Specification (SMI-S). This procedure describes the differences between the two methods.

About this task

To create a new IBMTSSVC_StorageVolume instance, follow these steps.

Procedure

Apply the CreateOrModifyElementFromStoragePool() method on the IBMTSSVC_Cluster that you use to create the new IBMTSSVC_StorageVolume, with these parameter specifications:
  • Virtualization Type: 0, 1, 2 for striped, sequential, or image.
  • Format flag: specifies the volume is formatted on creation or expansion.
  • BackendVolume REF: specifies the BackendVolumes to place the extents for the volume.
  • PreferredNode: sets the preferred node for the volume.
  • UnitDeviceID: sets the volume's Unit Device ID on clustered systems.
  • ElementName: sets the volume name at creation.
  • Autoexpand:
  1. Set the ElementType
    • An ElementType of 2 with the Standard Goal parameter creates a standard storage volume.
    • An ElementType of 8 creates a compressed storage volume.
  2. Set Size to the preferred volume size in bytes.
  3. Obtain the reference (CIMObjectPath) of the IBMTSSVC_ConcreteStoragePool instance from which you allocate an IBMTSSVC_StorageVolume.
  4. Set InPool to the reference (obtained in the previous step) of the pool from which the volume is allocated.

Results

The creation of a thin-provisioning volume based on SMI-S is available. To set the initial reserve value, use the Goal parameter only if the initial reserve value of the volume is not the default reserve value (0 KB). The instance of IBMTSSVC_StorageVolumeSetting is required to be created by IBMTSSVC_StorageConfigurationCapabilities::CreateSetting(). After the creation, modify the initial reserve value of this instance. The newly created instance will be taken as the Goal parameter to create the standard volume, and will be deleted automatically after 20 minutes.

What to do next

The following examples are parameters that are also available as part of the Volume Mirroring feature or Thin-Provisioned Volume feature.
Autoexpand
Used to attempt to maintain a fixed amount of unused real capacity on the volume, which is called the contingency capacity. The capacity is initially set to the real capacity, which is assigned when the volume is created. If you modify the real capacity, the contingency capacity is reset to be the difference between the used capacity and the real capacity.
Copies
Indicates the number of mirrored copies to create. Specify either 1 or 2.
Grainsize
Sets the grain size of a thin-provisioned volume, which is valid only if RealSize is set. Valid options include 32, 64, 128, or 256.
Import
Used to request that the system import a thin-provisioned storage volume from the storage pool.
IsSpaceEfficient
Flag that is used to indicate that the created volumes are thin-provisioned volumes. This flag does not apply to a modify operation.
Important: If the ElementType is set as 5, do not set this parameter.
RealSizeBytes and RealSizePercent
Indicates the real size of a thin-provisioned copy. These parameters cannot be used together.
Important: If the ElementType is set as 5, do not set this parameter.
WarningSizeBytes
Indicates the set point of used capacity at which point a warning is triggered. This parameter cannot be used with the WarningSizePercent parameter.
WarningSizePercent
Indicates the ratio of used capacity versus the volume provisioned capacity that triggers a warning. This parameter cannot be used with the WarningSizeBytes parameter.
AccessIOGrpList
Indicates the storage volume's access IO group list.