[Openstack] question on volume resize

John-Paul Robinson jpr at uab.edu
Thu Sep 5 21:36:13 UTC 2013


I'm trying to get some clarity on volume resize capabilities in OS.

As I understand it, this will be a Cinder feature in Havana.


Also, it appears that the nova-volume API in Essex through the Cinder
API in Grizzly are based on the same v1.0 of the block storage API.
That is, the features are consistent across these OS releases, but they
don't have support for volume resize.

In our Essex OpenStack deploy we are using Ceph RBD as our block
backend.  Ceph supports volume resizing:


I've successfully created a 1GB volume using nova volume commands and
then resized (grown) that volume via the Ceph backend to 2GB.
Unfortunately, Nova-volume doesn't recognize the added 1GB of space and
still reports the volume as 1GB in size.

In the scenario we are developing, we'd like to instantiate and track
volumes via nova-volume so we can benefit from the OS accounting API's
to track storage usage over time.  We'd also like to be able to grow
these volumes in place to add space for a user's block device and grow
the file system in that container to consume the newly added space.

Is there a way to update the recognized size of the volume in OS?

I would expect this to be a hack/work-around to tide us over until we
can move to Havana some time early 2014.

Any thoughts on how kludgey this would be and the likelihoods for
running afoul of maintaining a sane OS environment?



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