Report back actual volume / snapshot size.

[Matan Sabag]

Some drivers works with certain limitations to the volume size.
For example, ScaleIO has a limitation that the volume size must be with 8 GB granularity.

For example, if a user creates a volume of 2GBs in Cinder, ScaleIO actually creates 8GB volume in the back-end, but the user sees 2GB in Cinder.

We need to provide a way to return the actual size to driver.py and if its different from the original one we should log a warning or something about it.

[Walt Boring (walter-boring)]

You can do this today in your driver by returning a model update.

[John Griffith (john-griffith)]

This is very much a Scale-IO issue. Users of ScaleIO should be aware of this, and I would suggest that if you want to make this work document it, and then provide a model-update back from the create that increases the size in the DB (as hema suggested in IRC).

Other options include:
1. Error out and fail if the size isn't %8
2. Write a customer filter for the scheduler
3. If Scale-IO is the only backend in the deployment make sure your users know they have to do things in multiples of 8

[Matan Sabag (matan-sabag)]

Walter, returning model update will make the volume size correct, but that is not enough.

But that's not enough, the quota is still managed by cinder, and it won't be consistent with the actual size, we would like to update the quota within the driver.

That's also not enough, because volume creation time is after the quota has been registered, but still, it's the best we can offer at the moment.

Of course we letting our customers know that we are working in multiples of 8GB, but we can't count on it 100% and we want to make our data in OpenStack consistent with the real one.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/316811

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/316811
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=79d2d63ad868b6898bd13327f6b81712348883b6
Submitter: Jenkins
Branch: master

commit 79d2d63ad868b6898bd13327f6b81712348883b6
Author: Matan Sabag <email address hidden>
Date: Mon May 16 06:03:00 2016 -0700

    ScaleIO actual volume size model update

    Report back and update the actual volume size that is created in ScaleIO.

    ScaleIO volumes support sizes that are multiplies of 8 GB.
    This change updates the db with the real volume size.
    However, it is a partial fix, because the quota is not updated.

    The boolean property sio_round_volume_capacity specifies whether the
    user allows ScaleIO to create volumes with a size that is
    not a multiply of 8GB, hence causing ScaleIO to round it up.
    When set to False, creation of volumes with a size that is different
    than 8GB will fail.

    Change-Id: I10e699eab98715cf7c8cd79533fc9279e81dfbf6
    DocImpact:
    Partial-Bug: #1561560

[Sean McGinnis (sean-mcginnis)]

Unassigning due to no activity for > 6 months.

[Eric Harney (eharney)]

I believe this was fixed in https://review.openstack.org/316811

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: driverfixes/mitaka
Review: https://review.openstack.org/606139

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/606139
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=569cc8a2caa27e1667e69f30c97b8e0968617e32
Submitter: Zuul
Branch: driverfixes/mitaka

commit 569cc8a2caa27e1667e69f30c97b8e0968617e32
Author: Matan Sabag <email address hidden>
Date: Mon May 16 06:03:00 2016 -0700

    ScaleIO actual volume size model update

    Report back and update the actual volume size that is created in ScaleIO.

    ScaleIO volumes support sizes that are multiplies of 8 GB.
    This change updates the db with the real volume size.
    However, it is a partial fix, because the quota is not updated.

    The boolean property sio_round_volume_capacity specifies whether the
    user allows ScaleIO to create volumes with a size that is
    not a multiply of 8GB, hence causing ScaleIO to round it up.
    When set to False, creation of volumes with a size that is different
    than 8GB will fail.

    Change-Id: I10e699eab98715cf7c8cd79533fc9279e81dfbf6
    DocImpact:
    Partial-Bug: #1561560
    (cherry picked from commit 79d2d63ad868b6898bd13327f6b81712348883b6)