Can no longer explicitly configure the libvirt cache mode for disk devices

Bug #1086386 reported by David McNally
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
OpenStack Compute (nova)
Fix Released
Medium
David McNally

Bug Description

Can no longer explicitly configure the libvirt cache mode for disk devices

In past versions of Nova it was possible to explicitly configure the cache mode of disks via the libvirt XML template. The new approach makes this a derived setting of either “none” or “writethrough” based on the support of O_DIRECT. Whilst this provides a good set of default settings it removes the ability of the cloud provider to use other modes such as “writeback” and “unsafe” which are valuable in certain configurations.

The proposed change would allow the cache mode to be directly specified via configuration settings so as to override the default behaviour.

Changed in nova:
assignee: nobody → David McNally (dave-mcnally)
Michael Still (mikal)
Changed in nova:
status: New → Triaged
importance: Undecided → Medium
Revision history for this message
OpenStack Infra (hudson-openstack) wrote : Fix proposed to nova (master)

Fix proposed to branch: master
Review: https://review.openstack.org/18042

Changed in nova:
status: Triaged → In Progress
Revision history for this message
OpenStack Infra (hudson-openstack) wrote : Fix merged to nova (master)

Reviewed: https://review.openstack.org/18042
Committed: http://github.com/openstack/nova/commit/faf8dceb639c1c70ef2b3277cfb0a2e370706f45
Submitter: Jenkins
Branch: master

commit faf8dceb639c1c70ef2b3277cfb0a2e370706f45
Author: David McNally <email address hidden>
Date: Thu Dec 13 15:03:13 2012 +0000

    Adding ability to specify the libvirt cache mode for disk devices

    In past versions of Nova it was possible to explicitly configure
    the cache mode of disks via the libvirt XML template. The current approach
    makes this a derived setting of either “none” or “writethrough” based
    on the support of O_DIRECT. Whilst this provides a good set of default
    settings it removes the ability of the cloud provider to use other
    modes such as “writeback” and “unsafe” which are valuable in certain
    configurations.

    This change allows the cache mode to be specified on a per-disk type
    basis. If a disk type does not have a cache mode specified then the
    default behaviour remains unchanged.

    DocImpact

    bug 1086386

    Change-Id: I3d296fe0b4b9b976db02db90ad69fd299cd2096a

Changed in nova:
status: In Progress → Fix Committed
Thierry Carrez (ttx)
Changed in nova:
milestone: none → grizzly-rc1
status: Fix Committed → Fix Released
Thierry Carrez (ttx)
Changed in nova:
milestone: grizzly-rc1 → 2013.1
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