openstack/openstack-manuals
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Add rate-limit volume copy bandwidth

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Rate-limit of volume copy bandwidth per each Cinder backend is
implemented in Kilo. This patch adds documentation for it.

Change-Id: I6b887cf67b6fd0abf0cacf99c30fbe6c45a5dad6
This commit is contained in:
Tomoki Sekiyama 2015-04-21 20:03:02 -04:00 committed by Tom Fifield
parent 85fe8eb8d5
commit 3175ebd7b6
2 changed files with 49 additions and 1 deletions
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47
doc/admin-guide-cloud/blockstorage/section_ratelimit-volume-copy-bandwidth.xml Normal file
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<?xml version="1.0" encoding="UTF-8"?>
<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="ratelimit-volume-copy-bandwidth">
<title>Rate-limit volume copy bandwidth</title>
<para>When you create a new volume from an image or an existing
volume, or when you upload a volume image to the Image Service,
large data copy may stress disk and network bandwidth.
To mitigate slow down of data access from the instances,
OpenStack Block Storage supports rate-limiting of volume data
copy bandwidth.</para>
<simplesect>
<title>Configure volume copy bandwidth limit</title>
<para>To configure the volume copy bandwidth limit, set the
<option>volume_copy_bps_limit</option> option in the
configuration groups for each back end in the
<filename>cinder.conf</filename> file. This option takes
the integer of maximum bandwidth allowed for volume data
copy in byte per second. If this option is set to
<literal>0</literal>, the rate-limit is disabled.</para>
<para>While multiple volume data copy operations are running
in the same back end, the specified bandwidth is divided to
each copy.</para>
<para>Example <filename>cinder.conf</filename> configuration file
to limit volume copy bandwidth of <literal>lvmdriver-1</literal>
up to 100 MiB/s:</para>
<programlisting language="ini">[lvmdriver-1]
volume_group=cinder-volumes-1
volume_driver=cinder.volume.drivers.lvm.LVMISCSIDriver
volume_backend_name=LVM_iSCSI
volume_copy_bps_limit=104857600</programlisting>
<note>
<para>This feature requires libcgroup to set up blkio cgroup
for disk I/O bandwidth limit. The libcgroup is provided
by the <package>cgroup-bin</package> package in Debian
and Ubuntu, or by the <package>libcgroup-tools</package>
package in Fedora, Red Hat Enterprise Linux, CentOS, openSUSE, and
SUSE Linux Enterprise.</para>
</note>
<note>
<para>Some back ends which use remote file systems such as NFS
are not supported by this feature.</para>
</note>
</simplesect>
</section>

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doc/admin-guide-cloud/ch_blockstorage.xml
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@ -120,7 +120,7 @@
xlink:href="http://docs.openstack.org/user-guide/enduser/cli_nova_launch_instance_from_volume.html"
>Launch an instance from a volume</link> section
in the <link
xlink:href="http://docs.openstack.org/user-guide/index.html"
xlink:href="http://docs.openstack.org/user-guide/"
><citetitle>OpenStack End User
Guide</citetitle></link>.</para>
</section>
@ -151,6 +151,7 @@
<xi:include href="blockstorage/section_volume_number_weighter.xml"/>
<xi:include href="blockstorage/section_consistency_groups.xml"/>
<xi:include href="blockstorage/section_driver_filter_weighing.xml"/>
<xi:include href="blockstorage/section_ratelimit-volume-copy-bandwidth.xml"/>
</section>
<section xml:id="troubleshooting-cinder-install">
<title>Troubleshoot your installation</title>