Create volume group from source creates backend volumes with no name

[David Rosales]

When creating a Storwize SVC group from a source group or a source group snapshot, volumes are created for each volume in the source successfully. However, these volumes are not given a backend name and as such, querying the backend for these volumes afterward is not possible.

[David Rosales (darosale)]

Are there any updates on this issue?

[xiaoqin (xiaoqin-li)]

I am not sure about the backend name you mean. Cinder choose the same backend as the source volume during create group-create-from-src operation, for example, the same pool, the same volume type. If you mean the display name of cinder volume, the display-name is usually set by user, not by cinder driver. You can get the volume info using cinder show after group-create-from-src operation.
For example, create two cinder volume first with size 1G and 2G
cinder create --volume-type svc47default 1
cinder create --volume-type svc47default 2
Then you get two volumes
stack@xqli186:~$ cinder list
+--------------------------------------+-----------+------+------+--------------+----------+-------------+
| ID | Status | Name | Size | Volume Type | Bootable | Attached to |
+--------------------------------------+-----------+------+------+--------------+----------+-------------+
| 14da197b-7c31-4c04-8f9b-f3a0efb907d2 | available | - | 1 | svc47default | false | |
| ad5ae761-dfc0-49eb-9d49-7d7fffed7116 | available | - | 2 | svc47default | false | |
+--------------------------------------+-----------+------+------+--------------+----------+-------------+
Then add these two volumes into a group and create group from source:
cinder group-update --add-volumes 14da197b-7c31-4c04-8f9b-f3a0efb907d2,ad5ae761-dfc0-49eb-9d49-7d7fffed7116 cc081269-88e8-4150-8fbe-fd40492e8d37
cinder group-create-from-src --source-group cc081269-88e8-4150-8fbe-fd40492e8d37

Then you will get four volumes:
stack@xqli186:~$ cinder list
+--------------------------------------+-----------+------+------+--------------+----------+-------------+
| ID | Status | Name | Size | Volume Type | Bootable | Attached to |
+--------------------------------------+-----------+------+------+--------------+----------+-------------+
| 14da197b-7c31-4c04-8f9b-f3a0efb907d2 | available | - | 1 | svc47default | false | |
| 5b6a0790-13d3-4445-b683-28521a9d6cd8 | available | - | 2 | svc47default | false | |
| ac72d284-826f-4e1e-9c0d-64d57ca4c297 | available | - | 1 | svc47default | false | |
| ad5ae761-dfc0-49eb-9d49-7d7fffed7116 | available | - | 2 | svc47default | false | |
+--------------------------------------+-----------+------+------+--------------+----------+-------------+
The cinder show output is:
stack@xqli186:~$ cinder show ac72d284-826f-4e1e-9c0d-64d57ca4c297
+--------------------------------+--------------------------------------+
| Property | Value |
+--------------------------------+--------------------------------------+
| attached_servers | [] |
| attachment_ids | [] |
| availability_zone | nova |
| bootable | false |
| consistencygroup_id | None |
| created_at | 2017-10-18T08:27:06.000000 ...

[David Rosales (darosale)]

I'm not seeing the volume getting created on the storage host. This should default to 'volume-<volume id>' right? This is the issue I was referencing in the description.

[xiaoqin (xiaoqin-li)]

Hi David, yes, the volume-ac72d284-826f-4e1e-9c0d-64d57ca4c297 is created on the backend storage. If the volume creation fails, there will exception in the logs and the group status will be error.

[Matthew Edmonds (edmondsw)]

I believe the issue here is that "name" and "provider_id" are None.

[xiaoqin (xiaoqin-li)]

Hi Mattew, cinder choose the same backend as the source volume during create group-create-from-src operation. As David said, the volume name is 'volume-<volume id>'in the backend storage. We do not use "name" and "provider_id" info. The "name" is displayname in cinder and it is input by the user. For example, "cinder create --display-name xxxxx". It is not necessary and not unique. It is only used in cinder, not used in backend storage.

[David Rosales (darosale)]

Invalidating this. I can see volumes on the storage with said ids.