Infortrend EonStor GSa 5000 Series Hardware Manual page 29

4. Pull the ejection handles to remove the whole controller from the enclosure.
5. Install the host board into the SAS expansion slot, then secure it with a screw.
a. If your system is GSa 5100, which has only one CPU, install the host boards in slots 7 and 8.
EonStor GSa 5000 Series Hardware Manual 2-7