HPE ProLiant DL345 Gen11 Service And Maintenance Manual page 274

Midplane: 4 LFF drive bay numbering Midplane: 4 LFF drive bay numbering
Rear: 4 LFF drive bay numbering Rear: 4 LFF drive bay numbering
SFF drive bay numbering SFF drive bay numbering
The following drive backplane options are supported in SFF drive configurations:
Front-end: 2 SFF, side-by-side (LFF chassis only)
2 SFF 24G x4 U.3 NVMe / SAS UBM3 BC
2 SFF 24G x4 U.3 NVMe / SAS UBM6 BC
Front- or rear-end: 2 SFF, stacked:
24G x4 U.3 NVMe / SAS UBM3 BC
24G x4 U.3 NVMe / SAS UBM6 BC
Front-end: 8 SFF
8 SFF 24G x1 U.3 NVMe / SAS UBM3 BC
8 SFF 24G x1 U.3 NVMe / SAS UBM6 BC
8 SFF 24G x4 U.3 NVMe / SAS UBM3 BC
8 SFF 24G x4 U.3 NVMe / SAS UBM6 BC
HPE ProLiant DL345 Gen11 Server Service and Maintenance Guide 274