I have 1 rhevm and 3 rhevh. Storage is Dell Compellent.
After redhat fix the 512Bytes limit, i should be able now to mount the iscsi store, so there should be a detailed process at storage it self so that all of the hypervisor will be able to become spm or able to connect to the storage pool immediately once the existing spm becomes on maintenance mode.
At the Storage, a server cluster should be created, then join all the rhevh as member. Go to all the rhevh and make sure that you will be able to login manualy on the iscsi LUN advertised by the storage so that HBA will be available on the servers at the cluster. Then all member should have been map on the volume intended as the storage for the rhevh.
at the rhevh, discover first the iscsi.
iscsiadm --mode discoverydb --type sendtargets --portal 192.168.1.1 --discover
assuming that the ip of storage iscsi is 192.168.1.1
then login.
iscsiadm -m node -l ---> it will login to all discovered portal.
then go back at the rhevm and try to activate rhevh, it should be able to become an SPM now.