This is Normal? Multipath

[Caffe Mocha]

Hello everyone,
I have recently built a system for the company I worked for, and the specs can be found below.
after reading the chasis user manual, I have figured out how to correctly attached the cable below backplane and HBAs.
freenas and volume is setup correctly (at least I think so) even the Multipath showed up in the menu .


My question is multipath page showed that from disk 1 ~ 8 has 4 sub-disk showing, but from multipath/disk9 to 12 has only 3 sub-disk showing. This is normal? or is there any hardware error or bad cable or faulty hardware?
This is my first time dealing with expanders. also
do have i to put in additional HBA so that I won't hit with Hba bandwidth bottleneck?
so any suggestions or comments are welcome.
Thank you

CPU: E5-2630L v4 x2
RAM: 64G
chasis : supermicro 216BE2C-R920LPB 12Gbps dual-expander backplane
HBA: IBM M1215 flashed to IT mode x 2
SSD : Micron S630DC x 12

 

[Ericloewe]

That doesn't seem right. How did you get four-way multipathing?

 

[Caffe Mocha]

Thank you for replying, Ericloewe
from what I've read from the chasis's user manual (page 156 / G7)
HBA 1 port 1 to Primary expander Port A
HBA 1 port 2 to second expander Port B
HBA 2 port 1 to Primary expander Port A
HBA 2 port 2 to second expander port B

I don't understand how four-way multipathing works but isn't it suppose to show four-way multipathing in all disks?
or should I try a different configuration . such as connecting all HBAs to Primary expander?

This is way over my head

 

[Ericloewe]

I'm far from being an expert on multipathing, but this is the first time I've heard of a setup like that. I kinda expect it to break things in odd ways.

Generally, you have one HBA connected to one expander, and another HBA connected to another expander, not the criss-cross setup you're using.

 

[Caffe Mocha]

I will try your recommendation first and see it turns out. what are the result I should expect? two-way multipath ?
Thanks again

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