Score:0

SAS channel speed and multiple disk setup

cn flag

I have the following setup and looking for recommendations on the 2 connection options:

  • 1x SAS Controller in HBA mode with 2x SAS Ports
  • 2 SAS cables with 4 SAS connectors each
  • 4x HDs with 6GB/s SAS speed

So I could connect all 4 HDs with 1 SAS cable to 1 SAS port on the controller or I could connect 2 HDs on each of the 2 SAS ports.

HD1+HD2 ---- Cable1 ----Controller port 1

HD1+HD2 ---- Cable2 ----Controller port 2

or

HD1+HD2+HD3+HD4----Cable1------Controller port1

Does it make a difference performance wise? Would the recommendation change if I do a RADI5 setup for the 4 disks? Would the recommendation change if I do a RADI10 setup for the 4 disks?

Score:0
ru flag

So I could connect all 4 HDs with 1 SAS cable to 1 SAS port on the controller or I could connect 2 HDs on each of the 2 SAS ports.

Doesn't matter.

What you call "SAS cable" seems to have a four-lane connector on one end like this:

enter image description here SFF-8087 (credits: Wikipedia)

All four lanes are independent of each other. The lanes in the other connector are equally independent.

If you remember practices from Parallel SCSI, forget about them. Just connect in the way that makes most sense to you. For me, it would make sense to first max out one cable and leave the other for later.

Does it make a difference performance wise? Would the recommendation change if I do a RAID5 setup for the 4 disks? Would the recommendation change if I do a RAID10 setup for the 4 disks?

Doesn't matter at all. For any RAID setup with loose cabling, make sure you mark well which cable goes where.

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