Sas/nvme backwards compatibility?

[gregsachs]

Possible/likely stupid question, but I’ll ask it;
I have an intel with 2.5” sas backplane and adapters. Are u.2 drives backwards compatible with sas or no?

 

[EffrafaxOfWug]

Nope, completely different protocols although some of the same connectors are used (SFF-8643 -> SFF-8639 for a PCIe mobo -> U2 for example).

Some controllers like the LSI 9400 series support both SAS and NVME, but not both over the same ports at the same time (IIRC you might need a proprietary cable to use it with NVME drives).

Edit: I think only the 9400 series is using 8643, regular U2 is indeed 8639 as i386 points out below but I think the connector on the motherboard is usually still an 8643.

 

[i386]

Nope, completely different protocols although some cards share the same connectors (SFF-8643).

Actually it's sff-8639 (think sff-8643 + 4 pcie lanes).
Specification: https://members.snia.org/document/dl/26489

 

[EffrafaxOfWug]

You're quite right, I was thinking again of the 9400 card which uses 8643 for both.

 

[gregsachs]

Ok, thanks! I thought that was the case, but then I thought I had seen a comment about the nvme drives working with pure sas.