20f780cd61
There are several instances of "Compute Service" and "compute service" in the upstream documentation. As was recently clarified in the docs mailing list, these should be "Compute service/s". This patch corrects all untagged instances inside normal <para> blocks. Change-Id: Idcd7aafa0ce463e70635cb1c883a2476c1d97b5e Partial-Bug: #1217503
199 lines
9.9 KiB
XML
199 lines
9.9 KiB
XML
<section xml:id="xensm" 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>XenAPI Storage Manager volume driver</title>
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<para>The Xen Storage Manager volume driver (xensm) is a XenAPI
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hypervisor specific volume driver, and can be used to provide
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basic storage functionality, including volume creation and
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destruction, on a number of different storage back-ends. It
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also enables the capability of using more sophisticated
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storage back-ends for operations like cloning/snapshots, and
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so on. Some of the storage plug-ins that are already supported
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in Citrix XenServer and Xen Cloud Platform (XCP) are:</para>
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<orderedlist>
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<listitem>
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<para>NFS VHD: Storage repository (SR) plug-in that stores
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disks as Virtual Hard Disk (VHD) files on a remote
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Network File System (NFS).</para>
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</listitem>
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<listitem>
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<para>Local VHD on LVM: SR plug-in that represents disks
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as VHD disks on Logical Volumes (LVM) within a
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locally-attached Volume Group.</para>
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</listitem>
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<listitem>
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<para>HBA LUN-per-VDI driver: SR plug-in that represents
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Logical Units (LUs) as Virtual Disk Images (VDIs)
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sourced by host bus adapters (HBAs). For example,
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hardware-based iSCSI or FC support.</para>
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</listitem>
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<listitem>
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<para>NetApp: SR driver for mapping of LUNs to VDIs on a
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NETAPP server, providing use of fast snapshot and
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clone features on the filer.</para>
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</listitem>
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<listitem>
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<para>LVHD over FC: SR plug-in that represents disks as
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VHDs on Logical Volumes within a Volume Group created
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on an HBA LUN. For example, hardware-based iSCSI or FC
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support.</para>
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</listitem>
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<listitem>
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<para>iSCSI: Base ISCSI SR driver, provides a LUN-per-VDI.
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Does not support creation of VDIs but accesses
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existing LUNs on a target.</para>
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</listitem>
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<listitem>
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<para>LVHD over iSCSI: SR plug-in that represents disks as
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Logical Volumes within a Volume Group created on an
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iSCSI LUN.</para>
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</listitem>
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<listitem>
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<para>EqualLogic: SR driver for mapping of LUNs to VDIs on
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a EQUALLOGIC array group, providing use of fast
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snapshot and clone features on the array.</para>
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</listitem>
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</orderedlist>
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<section xml:id="xensmdesign">
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<title>Design and operation</title>
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<simplesect>
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<title>Definitions</title>
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<itemizedlist>
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<listitem>
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<para><emphasis role="bold">Back-end:</emphasis> A
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term for a particular storage back-end. This
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could be iSCSI, NFS, NetApp, and so on.</para>
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</listitem>
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<listitem>
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<para><emphasis role="bold"
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>Back-end-config:</emphasis> All the
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parameters required to connect to a specific
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back-end. For example, for NFS, this would be
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the server, path, and so on.</para>
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</listitem>
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<listitem>
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<para><emphasis role="bold">Flavor:</emphasis>
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This term is equivalent to volume "types". A
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user friendly term to specify some notion of
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quality of service. For example, "gold" might
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mean that the volumes use a back-end where
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backups are possible. A flavor can be
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associated with multiple back-ends. The volume
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scheduler, with the help of the driver,
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decides which back-end is used to create a
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volume of a particular flavor. Currently, the
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driver uses a simple "first-fit" policy, where
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the first back-end that can successfully
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create this volume is the one that is
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used.</para>
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</listitem>
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</itemizedlist>
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</simplesect>
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<simplesect>
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<title>Operation</title>
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<para>The admin uses the nova-manage command detailed
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below to add flavors and back-ends.</para>
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<para>One or more <systemitem class="service"
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>cinder-volume</systemitem> service instances are
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deployed for each availability zone. When an instance
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is started, it creates storage repositories (SRs) to
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connect to the back-ends available within that zone.
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All <systemitem class="service"
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>cinder-volume</systemitem> instances within a
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zone can see all the available back-ends. These
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instances are completely symmetric and hence should be
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able to service any <literal>create_volume</literal>
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request within the zone.</para>
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<note>
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<title>On XenServer, PV guests required</title>
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<para>Note that when using XenServer you can only
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attach a volume to a PV guest.</para>
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</note>
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</simplesect>
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</section>
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<section xml:id="xensmconfig">
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<title>Configure XenAPI Storage Manager</title>
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<simplesect>
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<title>Prerequisites</title>
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<orderedlist>
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<listitem>
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<para>xensm requires that you use either Citrix
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XenServer or XCP as the hypervisor. The NetApp
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and EqualLogic back-ends are not supported on
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XCP.</para>
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</listitem>
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<listitem>
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<para>Ensure all <emphasis role="bold"
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>hosts</emphasis> running volume and
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Compute services have connectivity to the
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storage system.</para>
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</listitem>
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</orderedlist>
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</simplesect>
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<simplesect>
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<title>Configuration</title>
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<itemizedlist>
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<listitem>
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<para>
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<emphasis role="bold">Set the following
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configuration options for the nova volume
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service: (<systemitem class="service"
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>nova-compute</systemitem> also
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requires the volume_driver configuration
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option.)</emphasis>
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</para>
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<programlisting>
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--volume_driver="nova.volume.xensm.XenSMDriver"
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--use_local_volumes=False
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</programlisting>
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</listitem>
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<listitem>
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<para>
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<emphasis role="bold">You must create the
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back-end configurations that the volume
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driver uses before you start the volume
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service.</emphasis>
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</para>
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<screen><prompt>$</prompt> <userinput>nova-manage sm flavor_create <label> <description></userinput>
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<prompt>$</prompt> <userinput>nova-manage sm flavor_delete <label></userinput>
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<prompt>$</prompt> <userinput>nova-manage sm backend_add <flavor label> <SR type> [config connection parameters]</userinput></screen>
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<note>
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<para>SR type and configuration connection
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parameters are in keeping with the <link
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xlink:href="http://support.citrix.com/article/CTX124887"
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>XenAPI Command Line
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Interface</link>.</para>
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</note>
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<screen><prompt>$</prompt> <userinput>nova-manage sm backend_delete <back-end-id></userinput></screen>
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<para>Example: For the NFS storage manager
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plug-in, run these commands:</para>
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<screen><prompt>$</prompt> <userinput>nova-manage sm flavor_create gold "Not all that glitters"</userinput>
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<prompt>$</prompt> <userinput>nova-manage sm flavor_delete gold</userinput>
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<prompt>$</prompt> <userinput>nova-manage sm backend_add gold nfs name_label=myback-end server=myserver serverpath=/local/scratch/myname</userinput>
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<prompt>$</prompt> <userinput>nova-manage sm backend_remove 1</userinput></screen>
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</listitem>
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<listitem>
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<para>
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<emphasis role="bold">Start <systemitem
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class="service"
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>cinder-volume</systemitem> and
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<systemitem class="service"
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>nova-compute</systemitem> with the
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new configuration options.</emphasis>
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</para>
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</listitem>
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</itemizedlist>
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</simplesect>
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<simplesect>
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<title>Create and access the volumes from VMs</title>
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<para>Currently, the flavors have not been tied to the
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volume types API. As a result, we simply end up
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creating volumes in a "first fit" order on the given
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back-ends.</para>
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<para>Use the standard <command>euca-*</command> or
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OpenStack API commands (such as volume extensions) to
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create, destroy, attach, or detach volumes.</para>
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</simplesect>
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</section>
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</section>
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