diff --git a/aif.xsd b/aif.xsd
index 2b2327c..0eb5f22 100644
--- a/aif.xsd
+++ b/aif.xsd
@@ -324,7 +324,7 @@
                                                                             maxOccurs="unbounded"
                                                                             type="aif:t_part_flags"/>
                                                             </xs:sequence>
-                                                            <xs:attribute name="id" type="aif:t_nonempty"
+                                                            <xs:attribute name="id" type="xs:ID"
                                                                           use="required"/>
                                                             <xs:attribute name="name" type="aif:t_nonempty"
                                                                           use="optional"/>
@@ -361,7 +361,7 @@
                                                     <xs:element name="opt" minOccurs="0" maxOccurs="unbounded"
                                                                 type="aif:t_cmdopts"/>
                                                 </xs:sequence>
-                                                <xs:attribute name="source" type="aif:t_nonempty" use="required"/>
+                                                <xs:attribute name="source" type="xs:IDREF" use="required"/>
                                                 <!-- We validate this in-code because there's way too many and
                                                      it's way too variable per-host. -->
                                                 <xs:attribute name="type" type="aif:t_nonempty" use="required"/>
@@ -401,9 +401,9 @@
                                                         </xs:complexType>
                                                     </xs:element>
                                                 </xs:sequence>
-                                                <xs:attribute name="id" type="aif:t_nonempty" use="required"/>
+                                                <xs:attribute name="id" type="xs:ID" use="required"/>
                                                 <xs:attribute name="name" type="aif:t_nonempty" use="required"/>
-                                                <xs:attribute name="source" type="aif:t_nonempty" use="required"/>
+                                                <xs:attribute name="source" type="xs:IDREF" use="required"/>
                                             </xs:complexType>
                                         </xs:element>
                                     </xs:sequence>
@@ -417,94 +417,74 @@
                             <!-- BEGIN LVM -->
                             <xs:element name="lvm" minOccurs="0" maxOccurs="1">
                                 <xs:complexType>
-                                    <xs:all minOccurs="1" maxOccurs="1">
-                                        <xs:element name="physicals" minOccurs="1" maxOccurs="1">
+                                    <xs:sequence>
+                                        <xs:element name="volumeGroup" minOccurs="1" maxOccurs="unbounded">
                                             <xs:complexType>
-                                                <xs:sequence minOccurs="1" maxOccurs="unbounded">
-                                                    <xs:element name="pv">
+                                                <xs:all>
+                                                    <xs:element name="physicalVolumes" minOccurs="1" maxOccurs="1">
                                                         <xs:complexType>
-                                                            <xs:attribute name="id" type="aif:t_nonempty"
-                                                                          use="required"/>
-                                                            <xs:attribute name="source" type="aif:t_nonempty"
-                                                                          use="required"/>
-                                                            <xs:attribute name="vg" type="aif:t_nonempty"
-                                                                          use="required"/>
-                                                        </xs:complexType>
-                                                    </xs:element>
-                                                </xs:sequence>
-                                            </xs:complexType>
-                                            <xs:unique name="uniq_pv_id">
-                                                <xs:selector xpath="aif:pv"/>
-                                                <xs:field xpath="@id"/>
-                                            </xs:unique>
-                                            <xs:unique name="uniq_pv_src">
-                                                <xs:selector xpath="aif:pv"/>
-                                                <xs:field xpath="@source"/>
-                                            </xs:unique>
-                                        </xs:element>
-                                        <xs:element name="volumes" minOccurs="1" maxOccurs="1">
-                                            <xs:complexType>
-                                                <xs:sequence minOccurs="1" maxOccurs="unbounded">
-                                                    <xs:element name="vg">
-                                                        <xs:complexType>
-                                                            <xs:all>
-                                                                <xs:element name="tags" minOccurs="0" maxOccurs="1">
+                                                            <xs:sequence>
+                                                                <xs:element name="pv" minOccurs="1"
+                                                                            maxOccurs="unbounded">
                                                                     <xs:complexType>
-                                                                        <xs:sequence minOccurs="1"
-                                                                                     maxOccurs="unbounded">
-                                                                            <xs:element name="tag"
-                                                                                        minOccurs="1"
-                                                                                        maxOccurs="unbounded"
-                                                                                        type="aif:t_nonempty"/>
-                                                                        </xs:sequence>
+                                                                        <xs:attribute name="id" type="xs:ID"
+                                                                                      use="required"/>
+                                                                        <xs:attribute name="source" type="xs:IDREF"
+                                                                                      use="required"/>
                                                                     </xs:complexType>
                                                                 </xs:element>
-                                                                <xs:element name="logicals" minOccurs="1"
-                                                                            maxOccurs="1">
+                                                            </xs:sequence>
+                                                        </xs:complexType>
+                                                    </xs:element>
+                                                    <xs:element name="logicalVolumes" minOccurs="1" maxOccurs="1">
+                                                        <xs:complexType>
+                                                            <xs:sequence>
+                                                                <xs:element name="lv" minOccurs="1"
+                                                                            maxOccurs="unbounded">
                                                                     <xs:complexType>
-                                                                        <xs:sequence minOccurs="1"
-                                                                                     maxOccurs="unbounded">
-                                                                            <xs:element name="lv" minOccurs="1"
-                                                                                        maxOccurs="unbounded">
-                                                                                <xs:complexType>
-                                                                                    <xs:attribute name="id"
-                                                                                                  type="aif:t_nonempty"
-                                                                                                  use="required"/>
-                                                                                    <xs:attribute name="name"
-                                                                                                  type="aif:t_nonempty"
-                                                                                                  use="required"/>
-                                                                                    <xs:attribute name="size"
-                                                                                                  type="aif:t_disksize"
-                                                                                                  use="required"/>
-                                                                                </xs:complexType>
-                                                                            </xs:element>
-                                                                        </xs:sequence>
+                                                                        <xs:attribute name="id" type="xs:ID"
+                                                                                      use="required"/>
+                                                                        <xs:attribute name="name" type="aif:t_nonempty"
+                                                                                      use="required"/>
+                                                                        <xs:attribute name="size" type="aif:t_disksize"
+                                                                                      use="required"/>
                                                                     </xs:complexType>
                                                                 </xs:element>
-                                                            </xs:all>
-                                                            <xs:attribute name="id" type="aif:t_nonempty"
-                                                                          use="required"/>
-                                                            <xs:attribute name="name" type="aif:t_nonempty"
-                                                                          use="required"/>
+                                                            </xs:sequence>
                                                         </xs:complexType>
-                                                        <xs:unique name="uniq_vg_tag">
-                                                            <xs:selector xpath="aif:tags"/>
-                                                            <xs:field xpath="tag"/>
-                                                        </xs:unique>
                                                     </xs:element>
-                                                </xs:sequence>
+                                                    <xs:element name="tags" minOccurs="0" maxOccurs="1">
+                                                        <xs:complexType>
+                                                            <xs:sequence>
+                                                                <xs:element name="tag" type="aif:t_nonempty"
+                                                                            minOccurs="1" maxOccurs="unbounded"/>
+                                                            </xs:sequence>
+                                                        </xs:complexType>
+                                                    </xs:element>
+                                                </xs:all>
+                                                <xs:attribute name="id" type="xs:ID" use="required"/>
+                                                <xs:attribute name="name" type="aif:t_nonempty" use="required"/>
                                             </xs:complexType>
-                                            <xs:unique name="uniq_vg_id">
-                                                <xs:selector xpath="aif:vg"/>
-                                                <xs:field xpath="@id"/>
-                                            </xs:unique>
-                                            <xs:unique name="uniq_vg_name">
-                                                <xs:selector xpath="aif:vg"/>
-                                                <xs:field xpath="@name"/>
+                                            <xs:unique name="uniq_vg_tags">
+                                                <xs:selector xpath="tags"/>
+                                                <xs:field xpath="tag"/>
                                             </xs:unique>
                                         </xs:element>
-                                    </xs:all>
+                                    </xs:sequence>
                                 </xs:complexType>
+                                <xs:unique name="uniq_vg_names">
+                                    <xs:selector xpath="volumeGroup"/>
+                                    <xs:field xpath="@name"/>
+                                </xs:unique>
+                                <!-- ??? doesn't seem to work. -->
+                                <xs:unique name="uniq_vg_lv">
+                                    <xs:selector xpath="volumeGroup/logicalVolumes/lv"/>
+                                    <xs:field xpath="@name"/>
+                                </xs:unique>
+                                <xs:unique name="uniq_vg_pv">
+                                    <xs:selector xpath="pv"/>
+                                    <xs:field xpath="@source"/>
+                                </xs:unique>
                             </xs:element>
                             <!-- END LVM -->
                             <!-- BEGIN MDADM -->
@@ -516,12 +496,12 @@
                                                 <xs:sequence minOccurs="1" maxOccurs="unbounded">
                                                     <xs:element name="member" minOccurs="1" maxOccurs="unbounded">
                                                         <xs:complexType>
-                                                            <xs:attribute name="source" type="aif:t_nonempty"
+                                                            <xs:attribute name="source" type="xs:IDREF"
                                                                           use="required"/>
                                                         </xs:complexType>
                                                     </xs:element>
                                                 </xs:sequence>
-                                                <xs:attribute name="id" use="required" type="aif:t_nonempty"/>
+                                                <xs:attribute name="id" use="required" type="xs:ID"/>
                                                 <xs:attribute name="name" use="required" type="aif:t_nonempty"/>
                                                 <xs:attribute name="meta" use="optional" default="1.2"
                                                               type="aif:t_raid_meta"/>
@@ -537,10 +517,6 @@
                                         </xs:element>
                                     </xs:sequence>
                                 </xs:complexType>
-                                <xs:unique name="uniq_array_id">
-                                    <xs:selector xpath="array"/>
-                                    <xs:field xpath="@id"/>
-                                </xs:unique>
                                 <xs:unique name="uniq_array_name">
                                     <xs:selector xpath="array"/>
                                     <xs:field xpath="@name"/>
@@ -557,12 +533,15 @@
                                                     <xs:element name="opt" minOccurs="1" maxOccurs="unbounded"
                                                                 type="aif:t_cmdopts"/>
                                                 </xs:sequence>
-                                                <xs:attribute name="source" type="aif:t_nonempty" use="required"/>
+                                                <xs:attribute name="source" type="xs:IDREF" use="required"/>
                                                 <xs:attribute name="target" type="aif:t_filepath" use="required"/>
                                             </xs:complexType>
-                                            <xs:unique name="uniq_mnts">
+                                            <xs:unique name="uniq_mnts_src">
                                                 <xs:selector xpath="aif:mount"/>
                                                 <xs:field xpath="@source"/>
+                                            </xs:unique>
+                                            <xs:unique name="uniq_mnts_tgt">
+                                                <xs:selector xpath="aif:mount"/>
                                                 <xs:field xpath="@target"/>
                                             </xs:unique>
                                         </xs:element>
@@ -748,6 +727,10 @@
                                         </xs:element>
                                     </xs:sequence>
                                 </xs:complexType>
+                                <xs:unique name="uniq_repo">
+                                    <xs:selector xpath="aif:repo"/>
+                                    <xs:field xpath="@name"/>
+                                </xs:unique>
                             </xs:element>
                             <xs:element name="mirrorList" maxOccurs="1" minOccurs="0">
                                 <xs:complexType>
@@ -771,10 +754,6 @@
                                         </xs:element>
                                     </xs:sequence>
                                 </xs:complexType>
-                                <xs:unique name="uniq_repos">
-                                    <xs:selector xpath="aif:repos"/>
-                                    <xs:field xpath="repo"/>
-                                </xs:unique>
                                 <xs:unique name="uniq_mirror">
                                     <xs:selector xpath="aif:mirrorList"/>
                                     <xs:field xpath="mirror"/>
@@ -828,10 +807,6 @@
                             </xs:element>
                         </xs:sequence>
                     </xs:complexType>
-                    <xs:unique name="uniq_script">
-                        <xs:selector xpath="aif:script"/>
-                        <xs:field xpath="@order"/>
-                    </xs:unique>
                 </xs:element>
                 <!-- END SCRIPTS -->
             </xs:all>
diff --git a/docs/urls b/docs/urls
new file mode 100644
index 0000000..a9da2b4
--- /dev/null
+++ b/docs/urls
@@ -0,0 +1,5 @@
+libblockdev/python gobject-introspection ("gi") API reference:
+https://lazka.github.io/pgi-docs/
+
+example of using above for LVM:
+https://github.com/storaged-project/libblockdev/blob/master/tests/lvm_test.py
\ No newline at end of file
diff --git a/examples/aif.xml b/examples/aif.xml
index 920859d..7ff7575 100644
--- a/examples/aif.xml
+++ b/examples/aif.xml
@@ -55,20 +55,26 @@
             </luksDev>
         </luks>
         <lvm>
-            <physicals>
-                <!-- "size" refers to the size used of the LV for this VG. -->
-                <pv id="pv1" source="lvm_member1" vg="vg1"/>
-            </physicals>
-            <volumes>
-                <vg id="vg1" name="group1">
-                    <tags>
-                        <tag>data</tag>
-                    </tags>
-                    <logicals>
-                        <lv id="lv1" name="logical1" size="100%"/>
-                    </logicals>
-                </vg>
-            </volumes>
+            <volumeGroup id="vg1" name="group1">
+                <tags>
+                    <tag>data</tag>
+                    <tag>misc</tag>
+                </tags>
+                <physicalVolumes>
+                    <pv id="pv1" source="lvm_member1"/>
+                </physicalVolumes>
+                <logicalVolumes>
+                    <lv id="lv1" name="logical1" size="100%"/>
+                </logicalVolumes>
+            </volumeGroup>
+            <volumeGroup id="vg2" name="group2">
+                <physicalVolumes>
+                    <pv id="pv2" source="lvm_member1"/>
+                </physicalVolumes>
+                <logicalVolumes>
+                    <lv id="lv2" name="logical1" size="100%"/>
+                </logicalVolumes>
+            </volumeGroup>
         </lvm>
         <mdadm>
             <!-- level can be 0, 1, 4, 5, 6, or 10. RAID 1+0 (which is different from mdadm RAID10) would be done by