>
> The solution is conceptually simple. We add a new API microversion in
> Cinder that adds and optional parameter called "generic_keep_source"
> (defaults to False) to both migrate and retype operations.
>
> This means that if the driver optimized migration cannot do the
> migration and the generic migration code is the one doing the migration,
> then, instead of our final step being to swap the volume id's and
> deleting the source volume, what we would do is to swap the volume id's
> and move all the snapshots to reference the new volume. Then we would
> create a user message with the new ID of the volume.
>
How would you propose to "move all the snapshots to reference the new volume"?
Most storage does not allow a snapshot to be moved from one volume to another.
really the only way a migration of a snapshot can work across all storage types
would be to incrementally copy the data from a source to a destination up to
the point of the oldest snapshot, create a new snapshot on the new volume, then
proceed through until all snapshots have been rebuilt on the new volume.
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> The solution is conceptually simple. We add a new API microversion in
> Cinder that adds and optional parameter called "generic_keep_source"
> (defaults to False) to both migrate and retype operations.
>
> This means that if the driver optimized migration cannot do the
> migration and the generic migration code is the one doing the migration,
> then, instead of our final step being to swap the volume id's and
> deleting the source volume, what we would do is to swap the volume id's
> and move all the snapshots to reference the new volume. Then we would
> create a user message with the new ID of the volume.
>
How would you propose to "move all the snapshots to reference the new volume"?
Most storage does not allow a snapshot to be moved from one volume to another.
really the only way a migration of a snapshot can work across all storage types
would be to incrementally copy the data from a source to a destination up to
the point of the oldest snapshot, create a new snapshot on the new volume, then
proceed through until all snapshots have been rebuilt on the new volume.
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OpenStack-operators@lists.openstack.org
http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack-operators