884ec3753e
In cloud admin guide, storage encrytion is missing in the comparion of storage types. An indicaion of the availability of ephemeral and block storage encryption could be addressed by adding a brief row releating to this in Table 1.2 Closes-Bug: #1473165 Change-Id: Ib89b716cdc89377f049935dd87e56cacf11762d0
121 lines
4.6 KiB
XML
121 lines
4.6 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
|
|
<!DOCTYPE section [
|
|
<!ENTITY % openstack SYSTEM "entities/openstack.ent">
|
|
%openstack;
|
|
]>
|
|
<section xmlns="http://docbook.org/ns/docbook"
|
|
xmlns:xi="http://www.w3.org/2001/XInclude"
|
|
xmlns:xlink="http://www.w3.org/1999/xlink"
|
|
version="5.0"
|
|
xml:id="storage-concepts">
|
|
<title>Storage concepts</title>
|
|
<para>The OpenStack stack uses the following storage types:</para>
|
|
<table rules="all">
|
|
<caption>Storage types</caption>
|
|
<col width="33%"/>
|
|
<col width="33%"/>
|
|
<col width="33%"/>
|
|
<thead>
|
|
<tr>
|
|
<td>On-instance / ephemeral</td>
|
|
<td>Block storage (cinder)</td>
|
|
<td>Object Storage (swift)</td>
|
|
</tr>
|
|
</thead>
|
|
<tbody>
|
|
<tr>
|
|
<td>Runs operating systems and provides scratch space</td>
|
|
<td>Used for adding additional persistent storage to a virtual
|
|
machine (VM)</td>
|
|
<td>Used for storing virtual machine images and data</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Persists until VM is terminated</td>
|
|
<td>Persists until deleted</td>
|
|
<td>Persists until deleted</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Access associated with a VM</td>
|
|
<td>Access associated with a VM</td>
|
|
<td>Available from anywhere</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Implemented as a filesystem underlying OpenStack
|
|
Compute</td>
|
|
<td>Mounted via OpenStack Block Storage controlled protocol
|
|
(for example, iSCSI)</td>
|
|
<td>REST API</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Encryption is available</td>
|
|
<td>Encryption is available</td>
|
|
<td>Work in progress - Expected for the Mitaka release</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Administrator configures size setting, based on
|
|
flavors</td>
|
|
<td>Sizings based on need</td>
|
|
<td>Easily scalable for future growth</td>
|
|
</tr>
|
|
<tr>
|
|
<td>Example: 10 GB first disk, 30 GB/core second disk</td>
|
|
<td>Example: 1 TB "extra hard drive"</td>
|
|
<td>Example: 10s of TBs of data set storage</td>
|
|
</tr>
|
|
</tbody>
|
|
</table>
|
|
|
|
<para>You should note that:<itemizedlist>
|
|
<listitem>
|
|
<para><emphasis>You cannot use OpenStack Object Storage like a
|
|
traditional hard drive.</emphasis> The Object Storage relaxes some
|
|
of the constraints of a POSIX-style file system to get other gains.
|
|
You can access the objects through an API which uses HTTP.
|
|
Subsequently you don't have to provide atomic operations (that is,
|
|
relying on eventual consistency), you can scale a storage system
|
|
easily and avoid a central point of failure.</para>
|
|
</listitem>
|
|
<listitem>
|
|
<para><emphasis>The OpenStack Image service is used to manage
|
|
the virtual machine images in an OpenStack cluster, not
|
|
store them.</emphasis> It provides an abstraction to different
|
|
methods for storage - a bridge to the storage, not the storage
|
|
itself.</para>
|
|
</listitem>
|
|
<listitem>
|
|
<para><emphasis>The OpenStack Object Storage can function on its
|
|
own.</emphasis> The Object Storage (swift) product can be
|
|
used independently of the Compute (nova) product.</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
</para>
|
|
<variablelist>
|
|
<title>Command-line clients and other interfaces</title>
|
|
<varlistentry>
|
|
<term>swift client</term>
|
|
<listitem>
|
|
<para>Enables users to submit commands to the REST API through
|
|
a command-line client authorized as either a admin user,
|
|
reseller user, or swift user.</para>
|
|
</listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>swift-init</term>
|
|
<listitem><para>Script that initializes the building of the ring
|
|
file, takes daemon names as parameter and offers commands.
|
|
Documented in
|
|
<link xlink:href="http://docs.openstack.org/developer/swift/admin_guide.html#managing-services">http://docs.openstack.org/developer/swift/admin_guide.html#managing-services</link>.</para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>swift-recon</term>
|
|
<listitem><para></para></listitem>
|
|
</varlistentry>
|
|
<varlistentry>
|
|
<term>swift-ring-builder</term>
|
|
<listitem><para>Storage ring build and rebalance utility.
|
|
Documented in <link
|
|
xlink:href="http://docs.openstack.org/developer/swift/admin_guide.html#managing-the-rings">http://docs.openstack.org/developer/swift/admin_guide.html#managing-the-rings</link>.</para></listitem>
|
|
</varlistentry>
|
|
</variablelist>
|
|
</section>
|