Has anybody tried the SuperMicro 846 passive backplane with SAS 12Gb/s ?

[Wondersausage]

I have the SuperMicro CSE-SC846A-R1200B chassis with the 24-port discrete passive backplane (the one with 6 4-lane SAS connectors, no port multiplier). It was designed for 3/6 Gb SAS. Has anybody tried it with 12 Gb SAS devices?

It looks like neither the MegaRAID controllers or the 12 Gb/s drives have any way to force 6 Gb operation, so if the backplane won't work I'll have to buy the SATA versions of the drives.

 

[PigLover]

Yes. All of the 'tq' backplanes will work with 12gb/s SAS. It's not supported but it works. Use good cables.

 

[Wondersausage]

Yes. All of the 'tq' backplanes will work with 12gb/s SAS. It's not supported but it works. Use good cables.

Hm thanks but this isn't a TQ, it's the 846A (6 x SFF8087). I just looked at Supermicro's backplane list and the 846A is listed under SAS1, but the specs page for my chassis say "3Gb/6Gb support" so that's pretty confusing. It sounds a lot like the 846A was engineered for 3Gb/s but managed to work fine at 6Gbp/s. Sounds like it might be pushing it to expect 12Gb/s.

Chassis: Super Micro Computer, Inc. - Products | Chassis | 4U | SC846A-R1200B
Backplane: http://www.supermicro.com/manuals/other/BPN-SAS-846A.pdf

 

[nephri]

If you use an adaptor cable SFF-8643 (from your HBA) to SFF-8087 (to your backplane) you whould be able to negociate the link to 12Gb/s.
SM don't support it officially but it should work.

 

[MiniKnight]

I haven't done it with this model, but inside a chassis is a short run for SAS and I've used SAS1 backplanes with SAS3 before like @PigLover says.

 

[PigLover]

Hm thanks but this isn't a TQ, it's the 846A (6 x SFF8087)./QUOTE]
I've done this with "A" series backplanes too (specifically, a 216A). The traces are longer so there is more risk of noise levels that could be troublesome but in general it does work. For home/lab should be fine. Not sure I'd do it in a production environment.

 

[hindutool]

In response to your question about the bpn-sas-846A. per supermicro, this board is compatible with SAS (3gb/s) and SAS2 (6Gb/s). What about SAS3 (12gb/s)? Well I haven't had a chance to to test the speeds but I just bought a SC846 36 bay behemoth from eBay. So I thought... I really want SAS3! The backplanes in the system were the BPN-SAS2-826-EL1 and BPN-SAS2-846-EL1. I swapped then out for a BPN-SAS3-826A-NV4 and a BPN-SAS-846A (no SAS3 Direct attached manufactured yet per supermicro). I connected these after much toil and trouble (one month of figuring out how to install them in the limited space of the chassis) to two RES3TV360 expanders (several lacerations, failed acrylic cuttings and many failed pvc pipe brackets). These are connected to an LSI 9361-8i RAID controller. the 2 Drives are WD 6TB 12Gb/s SAS3 Drives. On Boot up they are recognized just fine. BPN-SAS-846A works with SAS3 as it is just a passthrough backplane. Is the cabling a mess? Yes.... but definitely worth the effort. SFF-8087 to SFF-8643 cables...6 of them. Is the bottle neck with the cabling, sure... but it works. Please spread the word. I have pictures and when I get a chance, will put a step by step process of my build. I could not find an answer to this question so I took a gamble blew some casino earnings on the parts and gave it a go!