SC846... NVMe?

[kapone]

That is the premise I was addressing. But ...

- If you connect non-12G devices (i.e. no SAS3) however many [e.g., 24x SATA3 SSDs], the total bandwidth will NOT exceed 6 GB/s (typical max is 4-5 GB/s).
- You are definitely bottlenecked, but it is NOT by PCIe bandwidth.

Try it ...

So...you have a wide SAS3 connection between expander/backplane and your HBA. But...you're using SATA3 devices at the endpoints. ok...

Assuming each SATA3 SSD is ~500MBps, that's 24x500MBps = 12,000MBps = ~12GBps. You're bottlenecked by the SAS3 (wide) connection itself.

Assuming your SATA3 SSDs are slower than that...well, do the math.

I don't understand the point you're trying to make.

 

[UhClem]

So...you have a wide SAS3 connection between expander/backplane and your HBA. But...you're using SATA3 devices at the endpoints. ok...

Assuming each SATA3 SSD is ~500MBps, that's 24x500MBps = 12,000MBps = ~12GBps. You're bottlenecked by the SAS3 (wide) connection itself.

Fallacy ... since the PCIe g3 x8 max is 7 GB/s (which is < 12 GB/s)

I don't understand the point you're trying to make.

(With all your storage) If YOU actually put 18-24 SATA3 SSDs, each capable of 400+ MB/s, on a SAS3 expander, which is dual-linked/"wide" to a PCIe g3 x8 SAS3 HBA, then YOU will experience a max throughput limit of <6 GB/s.

The point: You have a knowledge gap regarding SAS3 expanders.

 

[kapone]

The point: You have a knowledge gap regarding SAS3 expanders

Ok.