Hmm Im not sure why some sas drives would appear as disk only while other show as multipath. Hopefully someone else has some ideas.
I recall reading a post where someone had some sas drives that were appearing twice as 2 paths, but not recognized as multipath and they had to create the multipath labels manually. Is that any chance what your seeing or is it for sure some sas drives only getting one path while others are getting 2 along with the multipath label?
Thanks for confirming my suspicion on the sata and sas on the same backplane/controller. I was pretty sure Dell's statement on not mixing them was support from the perspective of a H7**/H8*** raid controllers, and that they work just fine as separate freenas volumes.