Update: I checked the log-file /var/log/vdsm/vdsm.log and found this message: 2019-04-14 10:40:40,323+0200 INFO (jsonrpc/0) [storage.StorageDomain] sdUUID=f68db244-c11c-4dd1-9001-26a05071b4da (fileSD:540) 2019-04-14 10:40:40,326+0200 INFO (jsonrpc/0) [storage.StoragePool] Creating pool directory '/rhev/data-center/1de9e54a-5e57-11e9-ba26-00163e16c73a' (sp:634) 2019-04-14 10:40:40,327+0200 INFO (jsonrpc/0) [storage.fileUtils] Creating directory: /rhev/data-center/1de9e54a-5e57-11e9-ba26-00163e16c73a mode: None (fileUtils:199) 2019-04-14 10:40:40,327+0200 INFO (jsonrpc/0) [storage.SANLock] Acquiring host id for domain f68db244-c11c-4dd1-9001-26a05071b4da (id=250, async=False) (clusterlock:29 4) 2019-04-14 10:40:41,292+0200 INFO (vmrecovery) [vdsm.api] START getConnectedStoragePoolsList(options=None) from=internal, task_id=61946b04-7df3-410e-8f05-ad8a17a13915 (api:48) 2019-04-14 10:40:41,292+0200 INFO (vmrecovery) [vdsm.api] FINISH getConnectedStoragePoolsList return={'poollist': []} from=internal, task_id=61946b04-7df3-410e-8f05-ad 8a17a13915 (api:54) 2019-04-14 10:40:41,292+0200 INFO (vmrecovery) [vds] recovery: waiting for storage pool to go up (clientIF:709) 2019-04-14 10:40:41,329+0200 INFO (jsonrpc/0) [vdsm.api] FINISH createStoragePool error=Cannot acquire host id: (u'f68db244-c11c-4dd1-9001-26a05071b4da', SanlockExcept ion(19, 'Sanlock lockspace add failure', 'No such device')) from=::ffff:192.168.122.168,33246, flow_id=74a96844, task_id=78af21d4-d8df-463f-b7fe-fe295d0e25ed (api:52) 2019-04-14 10:40:41,329+0200 ERROR (jsonrpc/0) [storage.TaskManager.Task] (Task='78af21d4-d8df-463f-b7fe-fe295d0e25ed') Unexpected error (task:875) Traceback (most recent call last): File "/usr/lib/python2.7/site-packages/vdsm/storage/task.py", line 882, in _run return fn(*args, **kargs) File "<string>", line 2, in createStoragePool File "/usr/lib/python2.7/site-packages/vdsm/common/api.py", line 50, in method ret = func(*args, **kwargs) File "/usr/lib/python2.7/site-packages/vdsm/storage/hsm.py", line 1003, in createStoragePool leaseParams) File "/usr/lib/python2.7/site-packages/vdsm/storage/sp.py", line 636, in create self._acquireTemporaryClusterLock(msdUUID, leaseParams) File "/usr/lib/python2.7/site-packages/vdsm/storage/sp.py", line 567, in _acquireTemporaryClusterLock msd.acquireHostId(self.id) File "/usr/lib/python2.7/site-packages/vdsm/storage/sd.py", line 889, in acquireHostId self._manifest.acquireHostId(hostId, async) File "/usr/lib/python2.7/site-packages/vdsm/storage/sd.py", line 476, in acquireHostId self._domainLock.acquireHostId(hostId, async) File "/usr/lib/python2.7/site-packages/vdsm/storage/clusterlock.py", line 325, in acquireHostId raise se.AcquireHostIdFailure(self._sdUUID, e) AcquireHostIdFailure: Cannot acquire host id: (u'f68db244-c11c-4dd1-9001-26a05071b4da', SanlockException(19, 'Sanlock lockspace add failure', 'No such device')) 2019-04-14 10:40:41,330+0200 INFO (jsonrpc/0) [storage.TaskManager.Task] (Task='78af21d4-d8df-463f-b7fe-fe295d0e25ed') aborting: Task is aborted: "Cannot acquire host id: (u'f68db244-c11c-4dd1-9001-26a05071b4da', SanlockException(19, 'Sanlock lockspace add failure', 'No such device'))" - code 661 (task:1181) 2019-04-14 10:40:41,330+0200 ERROR (jsonrpc/0) [storage.Dispatcher] FINISH createStoragePool error=Cannot acquire host id: (u'f68db244-c11c-4dd1-9001-26a05071b4da', SanlockException(19, 'Sanlock lockspace add failure', 'No such device')) (dispatcher:83) 2019-04-14 10:40:41,330+0200 INFO (jsonrpc/0) [jsonrpc.JsonRpcServer] RPC call StoragePool.create failed (error 661) in 1.01 seconds (__init__:312) 2019-04-14 10:40:42,882+0200 INFO (jsonrpc/2) [api.host] START getStats() from=::ffff:192.168.122.168,33246 (api:48) 2019-04-14 10:40:42,894+0200 INFO (jsonrpc/2) [vdsm.api] START repoStats(domains=()) from=::ffff:192.168.122.168,33246, task_id=889a11ff-b596-4111-bb96-33427c26a6c5 (api:48) Looks like it has some issue when IPv6 is disabled or am I misunderstanding the log message? Is there some way I can fix that without enabling IPv6 in that case?