47 lines
1.7 KiB
ReStructuredText
47 lines
1.7 KiB
ReStructuredText
.. _ratelimit_volume_copy_bandwidth:
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================================
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Rate-limit volume copy bandwidth
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================================
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When you create a new volume from an image or an existing volume, or
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when you upload a volume image to the Image service, large data copy
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may stress disk and network bandwidth. To mitigate slow down of data
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access from the instances, OpenStack Block Storage supports rate-limiting
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of volume data copy bandwidth.
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Configure volume copy bandwidth limit
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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To configure the volume copy bandwidth limit, set the
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``volume_copy_bps_limit`` option in the configuration groups for each
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back end in the ``cinder.conf`` file. This option takes the integer of
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maximum bandwidth allowed for volume data copy in byte per second. If
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this option is set to ``0``, the rate-limit is disabled.
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While multiple volume data copy operations are running in the same back
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end, the specified bandwidth is divided to each copy.
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Example ``cinder.conf`` configuration file to limit volume copy bandwidth
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of ``lvmdriver-1`` up to 100 MiB/s:
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.. code-block:: ini
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[lvmdriver-1]
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volume_group=cinder-volumes-1
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volume_driver=cinder.volume.drivers.lvm.LVMVolumeDriver
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volume_backend_name=LVM
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volume_copy_bps_limit=104857600
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.. note::
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This feature requires libcgroup to set up blkio cgroup for disk I/O
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bandwidth limit. The libcgroup is provided by the cgroup-tools package
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in Debian and Ubuntu, or by the libcgroup-tools package in Fedora,
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Red Hat Enterprise Linux, CentOS, openSUSE, and SUSE Linux Enterprise.
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.. note::
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Some back ends which use remote file systems such as NFS are not
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supported by this feature.
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