206 lines
9.3 KiB
XML
206 lines
9.3 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<section xml:id="vmware-vmdk-driver"
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xmlns="http://docbook.org/ns/docbook"
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xmlns:xi="http://www.w3.org/2001/XInclude"
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xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0">
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<title>VMware VMDK driver</title>
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<para>Use the VMware VMDK driver to enable management of the
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OpenStack Block Storage volumes on vCenter-managed data
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stores. Volumes are backed by VMDK files on data stores using
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any VMware-compatible storage technology such as NFS, iSCSI,
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FiberChannel, and vSAN.</para>
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<warning>
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<para>
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The VMware ESX VMDK driver is deprecated as of the Icehouse release
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and may be removed in Juno or a subsequent release. The VMware
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vCenter VMDK driver continues to be fully supported.
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</para>
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</warning>
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<simplesect>
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<title>Functional context</title>
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<para>The VMware VMDK driver connects to vCenter, through
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which it can dynamically access all the datastores visible
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from the ESX hosts in the managed cluster.</para>
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<para>When you create a volume, the VMDK driver creates a VMDK
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file on demand. The creation of this VMDK file is
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completed only when the volume is subsequently attached to
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an instance, because the set of datastores visible to the
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instance determines where to place the volume.</para>
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<para>The running vSphere VM is then automatically
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reconfigured to attach the VMDK file as an extra disk.
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Once attached, you can log in to the running vSphere VM to
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rescan and discover this extra disk.</para>
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</simplesect>
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<simplesect>
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<title>Configuration</title>
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<para>The recommended volume driver for OpenStack Block Storage is
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the VMware vCenter VMDK driver. When you configure the
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driver, you must match it with the appropriate OpenStack
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Compute driver from VMware and both drivers must point to
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the same server.</para>
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<para>For example, in the <filename>nova.conf</filename> file,
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use this option to define the Compute driver:</para>
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<programlisting>compute_driver=vmwareapi.VMwareVCDriver</programlisting>
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<para>In the <filename>cinder.conf</filename> file, use this
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option to define the volume driver:</para>
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<programlisting>volume_driver=cinder.volume.drivers.vmware.vmdk.VMwareVcVmdkDriver</programlisting>
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<para>The following table lists various options that the
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drivers support for the OpenStack Block Storage
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configuration (<filename>cinder.conf</filename>):</para>
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<xi:include href="../../../common/tables/cinder-vmware.xml"/>
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</simplesect>
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<simplesect>
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<title>VMDK disk type</title>
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<para>The VMware VMDK drivers support the creation of VMDK
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disk files of type <literal>thin</literal>, <literal>thick</literal>,
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or <literal>eagerZeroedThick</literal>. Use the
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<code>vmware:vmdk_type</code> extra spec key with the
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appropriate value to specify the VMDK disk file type.
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The following table captures the mapping between the extra
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spec entry and the VMDK disk file type:</para>
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<table rules="all">
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<caption>Extra spec entry to VMDK disk file type
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mapping</caption>
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<thead>
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<tr>
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<td>Disk file type</td>
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<td>Extra spec key</td>
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<td>Extra spec value</td>
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</tr>
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</thead>
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<tbody>
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<tr>
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<td>thin</td>
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<td>vmware:vmdk_type</td>
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<td>thin</td>
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</tr>
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<tr>
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<td>thick</td>
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<td>vmware:vmdk_type</td>
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<td>thick</td>
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</tr>
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<tr>
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<td>eagerZeroedThick</td>
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<td>vmware:vmdk_type</td>
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<td>eagerZeroedThick</td>
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</tr>
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</tbody>
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</table>
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<para>If no <code>vmdk_type</code> extra spec entry is
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specified, the default disk file type is
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<literal>thin</literal>.</para>
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<para>The example below shows how to create a
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<code>thick</code> VMDK volume using the appropriate
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<code>vmdk_type</code>:</para>
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<screen>
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<prompt>$</prompt> <userinput>cinder type-create thick_volume</userinput>
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<prompt>$</prompt> <userinput>cinder type-key thick_volume set vmware:vmdk_type=thick</userinput>
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<prompt>$</prompt> <userinput>cinder create --volume-type thick_volume --display-name volume1 1</userinput>
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</screen>
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</simplesect>
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<simplesect>
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<title>Clone type</title>
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<para>With the VMware VMDK drivers, you can create a volume
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from another source volume or from a snapshot point. The
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VMware vCenter VMDK driver supports clone types
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<literal>full</literal> and
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<literal>linked/fast</literal>. The clone type is
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specified using the <code>vmware:clone_type</code> extra
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spec key with the appropriate value. The following table
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captures the mapping for clone types:</para>
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<table rules="all">
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<caption>Extra spec entry to clone type mapping</caption>
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<thead>
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<tr>
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<td>Clone type</td>
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<td>Extra spec key</td>
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<td>Extra spec value</td>
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</tr>
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</thead>
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<tbody>
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<tr>
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<td>full</td>
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<td>vmware:clone_type</td>
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<td>full</td>
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</tr>
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<tr>
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<td>linked/fast</td>
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<td>vmware:clone_type</td>
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<td>linked</td>
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</tr>
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</tbody>
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</table>
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<para>If not specified, the default clone type is
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<literal>full</literal>.</para>
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<para>The following is an example of linked cloning from
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another source volume:</para>
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<screen>
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<prompt>$</prompt> <userinput>cinder type-create fast_clone</userinput>
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<prompt>$</prompt> <userinput>cinder type-key fast_clone set vmware:clone_type=linked</userinput>
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<prompt>$</prompt> <userinput>cinder create --volume-type fast_clone --source-volid 25743b9d-3605-462b-b9eb-71459fe2bb35 --display-name volume1 1</userinput>
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</screen>
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<para>Note: The VMware ESX VMDK driver ignores the extra spec
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entry and always creates a <literal>full</literal>
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clone.</para>
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</simplesect>
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<simplesect>
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<title>Supported operations</title>
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<para>The following operations are supported by the VMware
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vCenter and ESX VMDK drivers:</para>
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<itemizedlist>
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<listitem>
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<para>Create volume</para>
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</listitem>
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<listitem>
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<para>Create volume from another source volume.
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(Supported only if source volume is not attached
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to an instance.)</para>
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</listitem>
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<listitem>
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<para>Create volume from snapshot</para>
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</listitem>
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<listitem>
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<para>Create volume from glance image</para>
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</listitem>
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<listitem>
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<para>Attach volume (When a volume is attached to an
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instance, a reconfigure operation is performed on
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the instance to add the volume's VMDK to it. The
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user must manually rescan and mount the device
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from within the guest operating system.)</para>
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</listitem>
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<listitem>
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<para>Detach volume</para>
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</listitem>
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<listitem>
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<para>Create snapshot (Allowed only if volume is not
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attached to an instance.)</para>
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</listitem>
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<listitem>
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<para>Delete snapshot (Allowed only if volume is not
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attached to an instance.)</para>
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</listitem>
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<listitem>
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<para>Upload as image to glance (Allowed only if
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volume is not attached to an instance.)</para>
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</listitem>
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</itemizedlist>
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<note>
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<para>Although the VMware ESX VMDK driver supports these
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operations, it has not been extensively tested.</para>
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</note>
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</simplesect>
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<simplesect>
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<title>Data store selection</title>
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<para>When creating a volume, the driver chooses a data store
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which is connected to maximum number of hosts. This is
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meant to reduce the number of volume migrations while
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attaching the volume to instances. The volume needs to be
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migrated if the instance's ESX host cannot access the
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data store containing the volume. In case of ties, the
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data store with lowest space utilization is selected, where
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space utilization is defined by the metric
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<literal>(1 - freespace/totalspace)</literal>.</para>
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</simplesect>
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</section>
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