[ovirt-users] Host cannot access the Storage Domain(s) <UNKNOWN> attached to the Data Center

Dear All; I have oVirt Engine Version: 3.5.6.2-1.el6 with three nodesrunning standard Centos 6.7 64bit. The main data storage storage is on OpenFiler iScsi volume. After rebooting the three nodes; the main data storage domain is down and all the three hosts are marked as "Non Operational" When I try to activate any host; I get the below error message:- "Host XXXXX cannot access the Storage Domain(s) <UNKNOWN> attached to the Data Center Default. Setting Host state to Non-Operational." I have attached the engine and vdsm log. Best Regards Fawzy Ibrahim