Help: How to connect SuperMicro M28E1

[brmiller]

I thought I was pretty smart picking up an 8-bay 2.5" drive enclosure for $40 this morning, and thought I understood SAS and SATA pretty well, but now I'm confused. The M28E1 has 4 connectors that look like SATA but two are labeled "in" and two are labeled "in/out". I have a 3ware Inc 9550SX that has the 8087-type connector with four fan-out SATA connectors I have connected directly to drives in the past, so I "get" that SAS -> 4x SATA or so it would seem. So if I understand the M28E1 correctly, 2 SAS on the 2 "in" ports make for 8-drives and the other "in/out" ports can be used for daisy-chaining another enclosure or redundancy on the SAS HBA. Or something like that.

The question I have for all you experts is what HBA / cabling do I need to make this work? The guy I bought it from already sold his HBA and I didn't think to ask about brand and cabling. He did say he ran normal SATA SSDs in the enclosure, but some posts I've read say the M28E2 (big brother with 8 SAS inputs) does not support SSD.

Any guidance would be helpful.

 

[sfbayzfs]

I was tempted by one of those a while ago, but avoided it after I learned it was a SAS1 expander.

The E1 part means it has in integrated SAS expander, but that was only made in a SAS1 expander AFAIK, which is problematic, and low in bandwidth - it is much better for that particular 8-in-2 to get the direct SFF-8087 version. I have never seen the expander version of the backplane in person, but it sounds like it uses 2 SATA cables to connect 2 3Gbps SAS1 channels to the 8 drives if you only use 2 in, and those run at half speed for SATA, so you would be sharing 3Gbps total among 8 drives, and if you use the other 2 as in and don't daisy chain, that is still 6Gbps for 8 drives if you are using SATA SSDs, which isn't great, especially when you can get 48Gbps to them with the direct connect version.

With old laptop spinners under 2TB each, it would be OK, although not super fast, but not good for SSDs.