Why storage domain is going down with error "expected one metadata pv in vg"

Issue

• After upgrading to RHV 4.1 , the storage domain is not coming up and below error is shown in the vdsm logs.

2017-04-26 10:59:17,271+0200 ERROR (jsonrpc/3) [storage.StoragePool] Couldn't read from master domain (sp:1393)
Traceback (most recent call last):
  File "/usr/share/vdsm/storage/sp.py", line 1391, in getInfo
    msdInfo = self.masterDomain.getInfo()
  File "/usr/share/vdsm/storage/blockSD.py", line 1243, in getInfo
    info['vgMetadataDevice'] = self._manifest.getVgMetadataDevice()
  File "/usr/share/vdsm/storage/blockSD.py", line 487, in getVgMetadataDevice
    return os.path.basename(lvm.getVgMetadataPv(self.sdUUID))
  File "/usr/share/vdsm/storage/lvm.py", line 1430, in getVgMetadataPv
    (vgName, pvs))
UnexpectedVolumeGroupMetadata: Volume Group metadata isn't as expected: "reason=Expected one metadata pv in vg: a8922dfb-6545-40de-9bda-df10309a703d, vg pvs: [PV(uuid='Z
iMH3u-Aqqu-wIX3-6sQF-fTSQ-wrF5-Yo993m', name='/dev/mapper/3600c0ff0001a4699264fc35501000000', size='2999632003072', vg_name='a8922dfb-6545-40de-9bda-df10309a703d', vg_uu
id='ogwPjW-SgZV-82Ps-pJwg-0rEk-s2yd-V1JBPz', pe_start='135266304', pe_count='22349', pe_alloc_count='21553', mda_count='1', dev_size='2999996907520', mda_used_count='1',
 guid='3600c0ff0001a4699264fc35501000000')]"

• The VG, PV and LV are showing in the hypervisor and VMs are running fine.