I'm trying to expand my ZFS raid setup and I have used up all the available Sata-ports on my motherboard. I have read about SAS Expanders online and I think i have understood what they do. But one detail seems to be skipped everywhere I looked. I know that SAS Expanders are supposed to be connected (through sff-8087) to a dedicated RAID card. The controller I have found has a 8x pcie slot. Why does a SAS expander that is supposed to transfer the data through the RAID Controller need such a big bus? wouldn't a 1x pcie slot be enough for transfering configuration (or whatever) to the SAS-expander? Or does this imply that I can transfer the actual data though the PCIe bus and skipp the RAID card if I don't want hardware RAID and just want to attatch disks to be passed through to the os (as JBOD)?
SAS-Expander: "HP 24-Bay 6G SAS Expander Server Card - 8x SFF-8087, 1x SFF-8088, PCI-E - 487738-001 / 468406-B21"