# Storage Pool Capabilities XML format

- Overview
- Element and attribute overview

## Overview

The Storage Pool Capabilities XML will provide the information to determine what types of Storage Pools exist, whether the pool is supported, and if relevant the source format types, the required source elements, and the target volume format types.

The Storage Pool Capabilities XML provides more information than the `virConnectGetCapabilities` which only provides an enumerated list of supported pool types.

## Element and attribute overview

A query interface was added to the virConnect API's to retrieve the XML listing of the set of Storage Pool Capabilities (Since 5.2.0):

              virConnectGetStoragePoolCapabilities

The root element that emulator capability XML document starts with is named `storagepoolCapabilities`. There will be any number of `pool` child elements with two attributes `type` and `supported`. Each `pool` element may have a `poolOptions` or `volOptions` subelements to describe the available features. Sample XML output is:

    <storagepoolCapabilities>
      <pool type='dir' supported='yes'>
        <volOptions>
          <defaultFormat type='raw'</>
          <enum name='targetFormatType'>
            <value>none</value>
            <value>raw</value>
            ...
          </enum>
        </volOptions>
      </pool>
      <pool type='fs' supported='yes'>
        <poolOptions>
          <defaultFormat type='auto'</>
          <enum name='sourceFormatType'>
            <value>auto</value>
            <value>ext2</value>
            ...
          </enum>
        </poolOptions>
        <volOptions>
          <defaultFormat type='raw'</>
          <enum name='targetFormatType'>
            <value>none</value>
            <value>raw</value>
            ...
          </enum>
        </volOptions>
      </pool>
      ...
    </storagepoolCapabilities>

The following section decribes subelements of the `poolOptions` and `volOptions` subelements

`defaultFormat`
  For the `poolOptions`, the `type` attribute describes the default format name used for the pool source. For the `volOptions`, the `type` attribute describes the default volume name used for each volume.

`enum`
  Each enum uses a name from the list below with any number of `value` value subelements describing the valid values.
  `sourceFormatType`
    Lists all the possible `poolOptions` source pool format types.
  `targetFormatType`
    Lists all the possible `volOptions` target volume format types.