cannot create thin provisioned volume larger than free space

[Patrick East]

There is currently a check here https://github.com/openstack/cinder/blob/master/cinder/scheduler/filters/capacity_filter.py#L83 where it will only allow a volume to be placed if the size is less than free space on a backend. After that check it will take into account thin provisioning and allow you to over subscribe.

As an example if you have 100GB of free space you can create as many 99GB volumes as you want (up to the over subscription ratio), but can never create a 101GB volume even if it stays under the oversubscription ratio.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/185764

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/185764
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=75953752e41819b0d2ca770d4d13ed1ccaec685a
Submitter: Jenkins
Branch: master

commit 75953752e41819b0d2ca770d4d13ed1ccaec685a
Author: Xing Yang <email address hidden>
Date: Wed May 27 12:58:04 2015 -0400

    Fix capacity filter to allow oversubscription

    Currently the capacity filter does not allow oversubscrition
    if the free physical capacity is less than the new volume size.
    This was based on the assumption that a new thinly provisioned
    volume will be consumed right away. This assumption does not
    allow us to take full advantage of thin provisioning.

    The fix is to allow oversubscription if thin provisioning is
    supported and max_over_subscription_ratio is greater than or
    equal to 1. The free physical capacity will not be used to
    compare with the new volume size for a backend that supports
    oversubscription in thin provisioning. The oversubscription
    ratio and virtual free capacity will still be used to decide
    whether a backend can be chosen for thin provisioning.

    Closes-Bug: #1458976
    Change-Id: I4c8904445654db839c25ded420915f83c3756f94

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/188031

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/kilo
Review: https://review.openstack.org/188037

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/188031
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=ab017d98b1bb39d218bd93970c0e561c685b7dbf
Submitter: Jenkins
Branch: master

commit ab017d98b1bb39d218bd93970c0e561c685b7dbf
Author: Xing Yang <email address hidden>
Date: Wed Jun 3 10:40:26 2015 -0400

    Allow provisioning to reach max oversubscription

    Currently if provisioned ratio is equal to max_over_subscription_ratio,
    the capacity filter does not allow any more thin provisioning. This patch
    makes a change so that thin provisioning is allowed if provisioned ratio
    is equal to max_over_subscription_ratio; it will only stop provisioning
    if provisioned ratio is greater than max_over_subscription_ratio.

    Change-Id: Ibf13ef97472b80a1b59ffd4389a4ed2eacf67205
    Partial-Bug: #1458976

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/kilo
Review: https://review.openstack.org/188403

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/188037
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=28df54c5d1db9ebb766bd7b81962676c4e591cad
Submitter: Jenkins
Branch: stable/kilo

commit 28df54c5d1db9ebb766bd7b81962676c4e591cad
Author: Xing Yang <email address hidden>
Date: Wed May 27 12:58:04 2015 -0400

    Fix capacity filter to allow oversubscription

    Currently the capacity filter does not allow oversubscrition
    if the free physical capacity is less than the new volume size.
    This was based on the assumption that a new thinly provisioned
    volume will be consumed right away. This assumption does not
    allow us to take full advantage of thin provisioning.

    The fix is to allow oversubscription if thin provisioning is
    supported and max_over_subscription_ratio is greater than or
    equal to 1. The free physical capacity will not be used to
    compare with the new volume size for a backend that supports
    oversubscription in thin provisioning. The oversubscription
    ratio and virtual free capacity will still be used to decide
    whether a backend can be chosen for thin provisioning.

    Closes-Bug: #1458976
    Change-Id: I4c8904445654db839c25ded420915f83c3756f94
    (cherry picked from commit 75953752e41819b0d2ca770d4d13ed1ccaec685a)

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/188403
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=28bb8d27d57a034f5e9e78751ee87897bc72c6c2
Submitter: Jenkins
Branch: stable/kilo

commit 28bb8d27d57a034f5e9e78751ee87897bc72c6c2
Author: Xing Yang <email address hidden>
Date: Wed Jun 3 10:40:26 2015 -0400

    Allow provisioning to reach max oversubscription

    Currently if provisioned ratio is equal to max_over_subscription_ratio,
    the capacity filter does not allow any more thin provisioning. This patch
    makes a change so that thin provisioning is allowed if provisioned ratio
    is equal to max_over_subscription_ratio; it will only stop provisioning
    if provisioned ratio is greater than max_over_subscription_ratio.

    Change-Id: Ibf13ef97472b80a1b59ffd4389a4ed2eacf67205
    Partial-Bug: #1458976
    (cherry picked from commit ab017d98b1bb39d218bd93970c0e561c685b7dbf)