Libvirt: iothreads for disk devices

Registered by Sébastien Han on 2013-10-30

The goal here is to let Openstack exploit iothreads in libvirt (aka virtio-blk-data-plane in qemu).

Iothreads allow to handle IO tasks in dedicated userspace threads. They get rid of the single threaded IO processing within qemu, which is important when using multiple disks in parallel.

Blueprint information

Status:
Not started
Approver:
None
Priority:
Undefined
Drafter:
Sébastien Han
Direction:
Needs approval
Assignee:
Markus Zoeller (markus_z)
Definition:
Review
Series goal:
None
Implementation:
Unknown
Milestone target:
None

Related branches

Sprints

Whiteboard

There's a tonne of different storage types supported by Nova. Thus, asking Nova to find the best setting for each configuration would be cumbersome. This blueprint will add a new config flag in the libvirt option group named disk_driver_io_policy. This new flag would be set by the cloud administrators.

@Jordan: thanks for the clarification, afterthoughts my description wasn't really good.There's a tonne of different storage types supported by Nova. Thus, asking Nova to find the best setting for each configuration would be cumbersome. This blueprint will add a new config flag in the libvirt option group named disk_driver_io_policy. This new flag would be set by the cloud administrators.

@Jordan: thanks for the clarification, afterthoughts my description wasn't really good.

If you are still working on this, please re-submit via nova-specs. If not, please mark as obsolete, and add a quick comment to describe why. --johnthetubaguy (20th April 2014)

Updated the description of the blueprint to reflect what we suggest for Mitaka.
--alexschm (11th September 2015)

Gerrit topic: https://review.openstack.org/#q,topic:bp/libvirt-exploit-new-io-features,n,z

Addressed by: https://review.openstack.org/230968
    libvirt: iothreads for disk devices

Updated the description, this blueprint now only deals with iothreads, native IO mode will be handled in a separate blueprint
--alexschm (6th October 2015)

Gerrit topic: https://review.openstack.org/#q,topic:bp/libvirt-iothreads,n,z

Newton Cycle
========

2016-03-18:
Alex has left the team and I will take over. New proposed for Newton with the same
change: https://review.openstack.org/#/c/230968/
-- Markus Zoeller (markus_z)

Not approved for Newton, new proposal for Ocata

Ocata Cycle
=======
Addressed by: https://review.openstack.org/384871
    WIP: libvirt: iothreads (1/?)

(?)

Work Items

Work items:
Create a spec for this blueprint and submit it for Newton : DONE

This blueprint contains Public information 
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