VMAX: clone failed "A configuration mismatch was detected among members of your META device(s)"

[Carl Pecinovsky]

Start with a concatenated volume with two member metas. Now clone the volume. _create_clone_v2() attempts to create the target volume with the same geometry as the source. However, when creating the base volume with:

                    rc, baseVolumeDict, storageSystemName = (
                        self._create_composite_volume(
                            volume, baseVolumeName, volumeSizeInbits,
                            extraSpecs))

The base volume returned contains 2 metas. Now when the additional meta is added later, the target has a total of 3 metas.

        ----------------------------------------------------------------------
                               BCV DATA RDF DATA
                      ---------------------------- --------------------------
        Sym Cap Std Inv BCV Inv Pair R1 Inv R2 Inv Pair
        Dev (MB) Tracks Tracks State Tracks Tracks State
        ----------------------------------------------------------------------
    --> 0C30 5121 - - N/A - - N/A
        0C31 5121 - - N/A - - N/A
        0C35 10240 - - N/A - - N/A
        ----------------------------------------------------------------------
              20482 - - - -
        }

The CIM call to CreateElementReplica later fails:

2015-04-08 14:34:09.801 29045 DEBUG cinder.volume.drivers.emc.emc_vmax_utils [req-0af555f3-3f73-4af6-b33a-af48734b90d3 0688b01e6439ca32d698d20789d52169126fb41fb1a4ddafcebb97d854e836c9 1529ddbf28b749179063d26fb0947870 - - -] Return code is: 1. Error Description is: Create Replica at step Issuing CreateReplica:StorRepGroupCloneEstablish failed: C:ERROR_CLASS_SOFTWARE F:ERROR_FAMILY_FAILED R:1100017 L:2 C:ERROR_CLASS_SOFTWARE F:ERROR_FAMILY_FAILED R:1100017 Metadevice configuration error : "Establish failed" : 2 : 182 : "A configuration mismatch was detected among members of your META device(s)" @
  [1] com.emc.cmp.osls.se.osl.Replica.StorRepGroupCloneEstablish():1380
  [0] com.emc.cmp.osls.se.array.job.JOB_RepCreate.run():261
. wait_for_job_complete /usr/lib/python2.7/site-packages/cinder/volume/drivers/emc/emc_vmax_utils.py:294
2015-04-08 14:34:09.802 29045 ERROR cinder.volume.drivers.emc.emc_vmax_provision [req-0af555f3-3f73-4af6-b33a-af48734b90d3 0688b01e6439ca32d698d20789d52169126fb41fb1a4ddafcebb97d854e836c9 1529ddbf28b749179063d26fb0947870 - - -] Error Create Cloned Volume: Volume: volume-Image_csky_dual_cap6_volume_1-dd968d15-16d4 Source Volume:00B0D+volume-csky_simple2-78a13346-00000009-8231E2-26f66e9e-d4ad. Return code: 1. Error: Create Replica at step Issuing CreateReplica:StorRepGroupCloneEstablish failed: C:ERROR_CLASS_SOFTWARE F:ERROR_FAMILY_FAILED R:1100017 L:2 C:ERROR_CLASS_SOFTWARE F:ERROR_FAMILY_FAILED R:1100017 Metadevice configuration error : "Establish failed" : 2 : 182 : "A configuration mismatch was detected among members of your META device(s)" @
  [1] com.emc.cmp.osls.se.osl.Replica.StorRepGroupCloneEstablish():1380
  [0] com.emc.cmp.osls.se.array.job.JOB_RepCreate.run():261

It seems that the following flow does not guarantee a volume with a single meta:
self._create_composite_volume() --> self.provision.create_composite_volume() --> conn.InvokeMethod(
            'CreateOrModifyCompositeElement'...)

And the code in _create_clone_v2() assumes that it will be so that it ends up with a concatenated composite containing the same number of metas as the source.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/174044

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/174044
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=58556d2a16802444a325b7700eb11f8bf3f89b37
Submitter: Jenkins
Branch: master

commit 58556d2a16802444a325b7700eb11f8bf3f89b37
Author: Xing Yang <email address hidden>
Date: Wed Apr 15 15:33:59 2015 -0400

    Fixed issue with mismatched config in VMAX driver

    When the source and target volumes have different meta device
    configurations, clone volume will fail. This patch fixed the
    problem.

    Closes-Bug: #1442376
    Change-Id: If2f2c085596b0045d7af6762bddeb4cd59158a57