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52 lines
2.9 KiB
XML
52 lines
2.9 KiB
XML
<?xml version='1.0' encoding='utf-8' ?>
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<!DOCTYPE section PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
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<!ENTITY % BOOK_ENTITIES SYSTEM "cloudstack.ent">
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%BOOK_ENTITIES;
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]>
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<!-- Licensed to the Apache Software Foundation (ASF) under one
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or more contributor license agreements. See the NOTICE file
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distributed with this work for additional information
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regarding copyright ownership. The ASF licenses this file
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to you under the Apache License, Version 2.0 (the
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"License"); you may not use this file except in compliance
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with the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing,
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software distributed under the License is distributed on an
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"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
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KIND, either express or implied. See the License for the
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specific language governing permissions and limitations
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under the License.
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-->
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<section id="about-secondary-storage">
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<title>About Secondary Storage</title>
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<para>Secondary storage stores the following:</para>
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<itemizedlist>
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<listitem><para>Templates — OS images that can be used to boot VMs and can include additional configuration information, such as installed applications</para></listitem>
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<listitem><para>ISO images — disc images containing data or bootable media for operating systems</para></listitem>
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<listitem><para>Disk volume snapshots — saved copies of VM data which can be used for data recovery or to create new templates</para></listitem>
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</itemizedlist>
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<para>The items in secondary storage are available to all hosts in the scope of
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the secondary storage, which may be defined as per zone or per region.</para>
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<para>To make items in secondary storage available to all hosts throughout the cloud, you can
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add object storage in addition to the
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zone-based NFS Secondary Staging Store.
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It is not necessary to
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copy templates and snapshots from one zone to another, as would be required when using zone
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NFS alone. Everything is available everywhere.</para>
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<para>&PRODUCT; provides plugins that enable both
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OpenStack Object Storage (Swift,
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<ulink url="http://swift.openstack.org">swift.openstack.org</ulink>)
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and Amazon Simple Storage Service (S3) object storage.
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When using one of these storage plugins, you configure Swift or S3 storage for
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the entire &PRODUCT;, then set up the NFS Secondary Staging Store for each zone. The NFS
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storage in each zone acts as a staging area through which all templates and other secondary
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storage data pass before being forwarded to Swoft or S3.
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The backing object storage acts as a cloud-wide
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resource, making templates and other data available to any zone in the cloud.</para>
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</section>
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