How to understand the LSI HBA connector specs?

Solution 1:

Looks like you're planning another fun ZFS project, Sandra :)

For some clarity on SAS topology and the different methods of connecting devices, please see my post at: How exactly does a SAS SFF-8087 breakout cable work? + RAID/connection questions

As for the LSI SAS 9206-16e controller you're looking at, the device is very simple.

• "16e" stands for sixteen external ports. This card is only meant to interface with and external storage controller. It has no ability to link to internal server drives or backplanes.

• The four ports are SAS SFF-8088 ports. These are 4-lane external SAS ports. Each lane is a 6Gbps link, so you are carrying 4*6Gbps (24Gbps) bandwidth per cable and per port. So for four ports, that's 96Gbps total bandwidth.

The better question is really: what you're planning to connect to this controller?

Most external JBOD enclosures only accept two 4-lane SAS cables... so you'll be oversubscribed, depending on the disk density and storage layout.

Solution 2:

The connectors are identical. Each connector has 4 SAS lanes. Each lane supports 6 Gb/s, but the total bandwidth that the chipset can handle over 4 lanes bonded together is 2400 MB/s, which works out to about 18 Gb/s (about 6 Gb/s less that the total available bandwidth).

The port configuration describes how you are allowed to hook up the devices. The physical connectors each carry 4 lanes and the card supports up to 16 lanes total. You can use those lanes as either 16 individual lanes, 4 lanes bonded together, or 8 lanes bonded together. In any of those cases, you will need an appropriate fan-out cable or expander.