I purchased a Supermicro CSE216 2U chassis some time ago, and I’m now finally coming around to using the 24x2.5" hot swap bays and populate them with Kingston DC600M SATA drives. I ran into kind of a roadblock however: the cabling and HBAs required for the specific backplane to get all 24 ports working.
The case came with the BPN216-SAS2-EL1 backplane and SAS2-216EL1 expander card. It also came with a SFF-8087 to angled SFF-8087 cable, which was connected to a LSI 9201-8i HBA.
Here is the part that is confusing for me: The backplane expander card only has 3 SFF-8087 MiniSAS ports while the 9201-8i HBA has 2 ports. The single HBA supports 8 drives, so according to my logic, the entire backplane with its 3 ports should only support 12, not the full 24 drives.
Are there any splitters for the cables I am not aware of? Do I need to get more/different HBAs to make use of all the 24 ports? The manual also stated that the EL1 version with a single expander should support 24 drives, but I was not able to make out how exactly that would work and what is required.
Get enough HBAs with a total of 6 SFF/SAS x4 ports to directly connect to each of the backplane’s ports, this will give you native performancre of each drive
Get a SAS Expander with enough ports between the HBA (even a single port there would be enough) and the backplane. SAS Expanders are similar to ethernet switches, the drives are your ethernet clients and your HBA sits at the switch uplink port.
All drives connected to a SAS Expander share bandwidth so you might hit a bottleneck here depending on your use case. But note that the SAS Expander uses SAS between itself and the HBA, with 4 lanes of SAS3 it gets a full-duplex/bidirectional 48 Gb/s link, which is plenty fast for a few SATA drives (SATA3 only uses a 6 Gb/s half-duplex link).
If you look closely at the first image on the link you posted, there’s actually 2 expander/daughter boards visible. You’re missing one, so indeed only 12 of the 24 bays can be used. Request the 2nd daughter board from the seller (it should’ve been included with the chassis) or obtain one from a reseller/web source.
The answer is on page vii (preface) of the manual that you linked.
You have the SAS2-216EL1 expander card that is good to access all 24 drives.
Page 3-1 explains the difference between the SAS2-216EL1 and SAS2-216EL2 expander cards.
So, your setup is @aBav.Normie-Pleb 's answer 2. The expander card acts like a network switch and allows accessing all 24 drives. It connects back to the HBA via 1 or more cables. In case multiple cables are connected it balances communication between them. No setup necessary.
Connecting a single cable is sufficient to access all 24 drives. Adding a second cable will increase available bandwidth between expander card and HBA, but likely will be unnecessary in case you populate the chassis with HDDs. That’s likely why you only have a single cable.
