Virtual Storage Lifecycle Management API


Data Object - HostPlugStoreTopology(vim.host.PlugStoreTopology)

Property of
HostStorageDeviceInfo
Extends
DynamicData
See also
HostPlugStoreTopologyAdapter, HostPlugStoreTopologyDevice, HostPlugStoreTopologyPath, HostPlugStoreTopologyPlugin, HostPlugStoreTopologyTarget
Since
vSphere API Release 4.0

Data Object Description

This data object represents the plug-store topology on a host system. Through this data object, the storage structure of a system that utilizes the plug-store architecture can be presented.

The object entity-relationship diagram is modeled below: 

  {@code
  ------------------------------------------------------------
  |             0..N             0..N      0..N              |
  |   Plugin ----->  Device  ------>  Path  <------  Adapter |
  |                          <------   |    ------>          |
  |                          0,1       |          1          |
  |                                    |                     |
  |                                    | 0,1                 |
  |                                   \|/                    |
  |                                  Target                  |
  ------------------------------------------------------------
  }
Description and reasoning behind the relationships:

When a storage device driver is loaded, it claims a PCI device as a host bus adapter. This host bus adapter is represented as an Adapter. The PCI device identifier is a property on the HostBusAdapter in the Adapter.

Once the host bus adapter is on the system, the hardware bus is scanned. If a storage Device is found on the bus, the communication path to the Device from the the host bus adapter is represented by a Path. A Device may have more than one Path. How those Paths are composed to create a Device is determined by a storage Plugin.

When a storage Plugin is loaded, it claims a set of Paths. It groups these Paths into a set of Devices. Devices are hence associated with a set of Paths that might be used to provide a single logical device such as in the case of multipathing. Devices may be also composed of zero Paths meaning that they do not directly use a host bus adapter for communication with underlying storage.

The purpose of this data object is to represent the topology of storage as seen by the base plug-store system. There is some overlap with information in other objects such as ScsiTopology which is only applicable when a particular "native multipathing" plugin is used. This data object provides the complete inventory of Devices and Paths. Hence it provides a superset of Device mappings over data object such as ScsiTopology and Multipa

The use cases that this data object accommodates includes the following non-exhaustive list:

  • Enumerate paths on a host bus adapter.
  • Enumerate paths on a storage device.
  • Conveniently access the devices a host bus adapter is associated with by traversing the path.
  • Determine which plugin a device belongs.
  • Determine which paths are claimed by a plugin by accumulating the paths of all device of the plugin.
  • Determine which plugin a path belongs to by accessing its device and finding that device in the Plugin list.

Properties

Name Type Description
adapter*HostPlugStoreTopologyAdapter[]

List of host bus adapters in the plug store inventory.
device*HostPlugStoreTopologyDevice[]

List of devices in the plug store inventory.
path*HostPlugStoreTopologyPath[]

List of paths in the plug store inventory.
plugin*HostPlugStoreTopologyPlugin[]

List of plugins in the plug store inventory.
target*HostPlugStoreTopologyTarget[]

Partial list of targets as seen by the host. The list of targets may not be exhaustive on the host.
Properties inherited from DynamicData
None
*Need not be set
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