# Engines

Command Center allows cloud administrators to view
all storage instance specifications available for deployment on the cloud.

To view VPSA engine properties:

1. Click **Engines** in Command Center’s left menu panel.
2. Click the tabs to view properties per engine type:
   * [VPSA IO engines properties](#vpsa-io-engines-properties)
   * [VPSA App engines properties](#vpsa-app-engines-properties)
   * [VPSA Composite engines properties](#vpsa-composite-engines-properties)

<a id="vpsa-io-engines-properties"></a>

## VPSA IO engines properties

The **IO** tab displays the following properties per IO engine:

| **Property**           | **Description**                                                    |
|------------------------|--------------------------------------------------------------------|
| Name                   | IO Engine Name                                                     |
| Internal Type          | Internal type used by Nova for this engine                         |
| Memory                 | **Single virtual controller** RAM requirement for this IO engine   |
| VCPU                   | **Single virtual controller** VCPUs requirement for this IO engine |
| VPSAs / Object Storage | Count of VPSAs with this engine type, in this cloud                |

<a id="vpsa-app-engines-properties"></a>

## VPSA App engines properties

The **App** tab displays the following properties per App engine:

| **Property**           | **Description**                                     |
|------------------------|-----------------------------------------------------|
| Name                   | APP Engine Name                                     |
| Internal Type          | Internal type used by Nova for this engine          |
| Memory                 | RAM requirement for this APP engine                 |
| VCPU                   | VCPUs requirement for this APP engine               |
| VPSAs / Object Storage | Count of VPSAs with this engine type, in this cloud |

<a id="vpsa-composite-engines-properties"></a>

## VPSA Composite engines properties

The **Composite** tab displays the following properties per Composite engine:

| **Property**                                | **Description**                                                                                                                                                                                                                                                                                                                                                                              |
|---------------------------------------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| Category                                    | Composite engine type                                                                                                                                                                                                                                                                                                                                                                        |
| Controller Instance Type                    | Link to the image used for composite controller instances.<br/><br/>Click the sub-instance image link to display its properties:<br/><br/>* **Name**: Composite sub-instance engine name<br/>* **Internal Type**: Internal type used by Nova for this engine<br/>* **Memory**: RAM requirement for this sub-instance engine<br/>* **VCPU**: VCPUs requirement for this sub-instance engine   |
| Data Policy Partition Power                 | Swift partition power used for data policies for this composite engine type                                                                                                                                                                                                                                                                                                                  |
| Dedicated Controller Vcs                    | Count of dedicated controller VCs deployed for this composite engine type                                                                                                                                                                                                                                                                                                                    |
| Enable ZELB On Object Storage Creation      | Whether Zadara Extend load balancing is enabled on VPSA creation                                                                                                                                                                                                                                                                                                                             |
| Enforce Drive Add With VC Set               | Whether disk drives are automatically added when the VPSA is expanded by an additional VC set                                                                                                                                                                                                                                                                                                |
| Max Capacity In TiB                         | Maximum storage capacity supported by this composite engine type                                                                                                                                                                                                                                                                                                                             |
| Max Drives Per Proxy Storage VC             | Maximum disk drives that can be added to a proxy storage virtual controller                                                                                                                                                                                                                                                                                                                  |
| Metadata Partition Size In GiB              | Size in gigabytes of each Metadata partition                                                                                                                                                                                                                                                                                                                                                 |
| Metadata Partitions Per Proxystorage VC     | Metadata partitions allocated for each proxy storage virtual controller                                                                                                                                                                                                                                                                                                                      |
| Metadata Policy Partition Power             | Swift partition power used for metadata policies for this composite engine type                                                                                                                                                                                                                                                                                                              |
| Minimum VC Sets for Object Storage Creation | Minimum footprint in terms of virtual controller sets for this composite engine type                                                                                                                                                                                                                                                                                                         |
| Name                                        | Composite engine instance type name                                                                                                                                                                                                                                                                                                                                                          |
| Proxy Instance Type                         | Link to the image used for composite proxy instances<br/><br/>Click the sub-instance image link to display its properties:<br/><br/>* **Name**: Composite sub-instance engine name<br/>* **Internal Type**: Internal type used by Nova for this engine<br/>* **Memory**: RAM requirement for this sub-instance engine<br/>* **VCPU**: VCPUs requirement for this sub-instance engine         |
| Proxy Storage Instance Type                 | Link to the image used for composite storage proxy instances<br/><br/>Click the sub-instance image link to display its properties:<br/><br/>* **Name**: Composite sub-instance engine name<br/>* **Internal Type**: Internal type used by Nova for this engine<br/>* **Memory**: RAM requirement for this sub-instance engine<br/>* **VCPU**: VCPUs requirement for this sub-instance engine |
| Setup Partition Size In GiB                 | Allocation size in gigabytes for the composite instance setup partition                                                                                                                                                                                                                                                                                                                      |