Norco 4020 - each drive bay backplane has two sata ports... why?

[gigatexal]

Hey guys while putting the 3tb drives into their hotswap caddys I noticed that on the back of each drive plane on my norco 4020 there's two sata ports when I was thinking there'd only be one per drive. Why the two? Also, does this mean i will need another controller to power 16 drives?

 

[PigLover]

The backplanes are actually SAS and set up for dual-port. SAS is backward compatible with SATA, but only one port at a time will work.

Just cable to one of the two SATA ports per drive.

 

[gigatexal]

awesome thanks for the sanity check

i'm googling dual-port sas now

again much thanks