8ca13afc49
This will now require a separate section "Use Cases". This was originally within "Problem description", but use cases seems to be missed when it was filled out. This will hopefully improve spec submission. Change-Id: I3615ca5ff5c46851e682739a8343242e2f1b0a8d
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This work is licensed under a Creative Commons Attribution 3.0 Unported
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License.
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http://creativecommons.org/licenses/by/3.0/legalcode
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=============================================
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Add QoS capability to the IBM Storwize driver
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=============================================
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https://blueprints.launchpad.net/cinder/+spec/cinder-storwize-driver-qos
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Storwize driver can provide the QoS capability with the parameter of
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IO throttling, which caps the amount of I/O that is accepted. This
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blueprints proposes to add the QoS support for Storwize driver.
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Problem description
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===================
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Storwize backend storage can be enabled with the QoS support by limiting
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the amount of I/O for a specific volume. QoS has been implemented for
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some cinder storage drivers, and it is feasible for the storwize driver
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to add this feature as well.
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Use Cases
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=========
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Proposed change
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===============
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To enable the QoS for storwize driver, an extra spec with IOThrottling as the
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key needs to bind to a volume type. All the following changes apply to the
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Storwize driver code.
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Create volume:
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* If QoS is enabled and IOThrottling is available as the QoS key, set the I/O
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throttling of the volume into the specified IOThrottling value.
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Create clone volume:
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* If the QoS is set for the original volume, the target volume needs to set
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to the same QoS.
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Create snapshot:
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* The QoS attributes will be copied to the snapshot.
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Create volume from snapshot:
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* If QoS is enabled and IOThrottling is available as the QoS key, set the IO
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throttling of the volume into the specified IOThrottling value.
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Re-type volume:
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* If a volume type is changed, a different IOThrottling value will apply to
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the volume and the I/O of the volume needs to be set to the new IO
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throttling.
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Alternatives
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------------
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The proposed change follows the pattern, in which other drivers implement the
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QoS feature.
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Data model impact
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-----------------
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None.
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REST API impact
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---------------
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None.
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Security impact
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---------------
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None.
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Notifications impact
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--------------------
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None.
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Other end user impact
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---------------------
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None.
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Performance Impact
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------------------
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None.
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Other deployer impact
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---------------------
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The QoS for Storwize driver can be configurable with a configuration option
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in cinder.conf. An extra spec with the key of IOThrottling can bind to a
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volume type, so that the volumes with this volume type are guaranteed with
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an I/O throttling rate.
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Developer impact
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----------------
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None.
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Implementation
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==============
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Assignee(s)
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-----------
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Primary assignee:
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Vincent Hou
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Other contributors:
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TBD
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Work Items
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----------
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* Add a configuration option to allow the user the use the QoS for Storwize
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driver.
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* Add the QoS enablement check and set the I/O throttling in create volume.
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* Add the QoS enablement check and set the I/O throttling in create volume
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from snapshot.
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* Set the I/O throttling to the new volume acording to the original volume
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in create clone volume.
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* Copy the QoS attributes to the snapshot in create snapshot.
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* Change the I/O throttling of the volume if the volume type is changed.
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Dependencies
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============
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None.
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Testing
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=======
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* Unit tests need to be added to test the QoS for Storwize driver.
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Documentation Impact
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====================
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* Add how to configure the QoS for the Storwize driver in the document.
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References
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==========
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* Add QoS capability to the IBM storwize driver
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https://blueprints.launchpad.net/cinder/+spec/cinder-storwize-driver-qos
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