I have a working single path HA setup, the reason for this is that I don't (and you never should) want to mix FC and SATA shelves.
Let me take one my FCAL loops for an example:
Filer1 0a is attached to IN of the first controller of Shelf1
Filer2 0b is attached to IN of the second controller of Shelf1
Filer1 0b is attached to IN of the second controller of Shelf2
Filer2 0a is attached to IN of the first controller of Shelf2
This works with SyncMirror, all disks of every shelf (except the OS disks) are assigned to Filer1 and Filer2 takes over the IP's of Filer1 when Filer1 dies.
As far as I understood a good setup and working well.
Now I want to add 2 shelves in each loop but what I discover is that when I add one between I have to go from OUT to IN and in that way (in the Shelf1 loop) Filer2 sees the disks but tells me they are owned by Filer one.
On Filer2 I cannot remove the ownership and on Filer1 the disks are not seen or usable.
I have done a shelfchk and all leds are blinking but not from Filer2 to Shelf1, but only to Shelf3 (new one). This has something todo with the IN/OUT cabeling between the shelves.
What am I doing wrong here ? I need to have some "IN/IN" connection again.