The Supermicro backplane manuals for single expander chips always add JBOD cases through the primary backplane or the primary HBA. Why don't they add an additional HBA with external ports (e.g. LSI 9300-8e)? Consider this "home lab" scenario:

 

1.) Primary Case: Supermicro SC846E16

Backplane: Supermicro BPN-SAS2-846EL1 (single expander chip)

Mainboard: Supermicro X9DRi-F Dual LGA 2011

CPU: 2x Intel Xeon E5-2609 V2 4 Core

Memory: 64GB DDR3 ECC REG (4 x 16GB)

HBA: LSI 9300-8i (both HBA cables, 8 lanes, are connected to the primary backplane).

 

2.) Secondary Case: Supermicro SC846E16 

Backplane: Supermicro BPN-SAS2-846EL1 (single expander chip)

JBOD Power card: Supermicro CSE-PTJBOD-CB2

 

First Supermicro Option: Take the free port from the primary backplane and lead one cable to the secondary backplane.

--> Primary backplane has 8 lanes, secondary backplane has 4 lanes.

 

Second Supermicro Option: Attach only one port from the LSI 9300-8i HBA to the primary backplane and attach the second port from this HBA to the secondary backplane.

--> Primary backplane has 4 lanes, secondary backplane has 4 lanes.

 

Option, I ask for: Add an additional HBA e.g. LSI 9300-8e to the primary case. Lead both cables from this second HBA to the secondary backplane.

--> Primary backplane has 8 lanes, secondary backplane has 8 lanes.

 

 

What's wrong with my approach? Is it total BS? Wouldn't it be better to have 8 lanes in the secondary backplane?

 

I know, Unraid does not support more than 28 drives in protected arrays. But I hope it will be added in the future.

 

Edited January 22, 20197 yr by hawihoney

41 minutes ago, hawihoney said:

What's wrong with my approach?

Nothing, just needs the extra HBA.

Thanks, but would it be better than connecting the backplanes itself? I mean, 8 lanes per backplane instead of 4 lanes per backplane. Will it give any benefit?

 

It will double the available bandwidth, for SAS2/SATA3 it's 2200MB/s vs 4400MB/s usable, if it's an advantage depends on the devices connected.

Thanks you very much.

 

Hi hawihoney, 

 

I am new to this and i have the same backplane BPN-SAS2-846EL1 and LSI 9300-8i HBA as you and was wondering what cables you used to hook the hba up to the backplane? And should i use two or just one? Sorry to hijack the conversation. 

Edited February 21, 20206 yr by nugget
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