Device hierarchy

The API manages all block devices in machine’s local /dev/ directory, i.e. also remote disks (iSCSI, FcoE, ...), as long as there is appropriate device in local /dev/.

Each block device is represented by instance of CIM_StorageExtent or its subclasss.

LMI_StorageExtent represents all devices, which do not have any specific CIM_StorageExtent subclass.

Each volume group is represented by LMI_VGStoragePool.

Instances of LMI_VGStoragePool, CIM_StorageExtent and its subclasses compose an oriented graph of devices on the system. Devices are connected with these associations or their subclasses:

• CIM_BasedOn and is subclasses associates a block device to all devices, on which it directly depends on, for example a partition is associated to a disk, on which it resides, and MD RAID is associated to all underlying devices, which compose the RAID.
• LMI_VGAssociatedComponentExtent associates volume groups with its physical extents.
• LMI_LVAllocatedFromStoragePool associates logical volumes to their volume groups.

Example of two logical volumes allocated from volume group created on top of MD RAID with three devices.