HPE ProLiant DL320 Gen11 Maintenance And Service Manual page 206

All drives belong to box 1.
SAS or SATA drives are supported.
To manage the hot-plug SAS drive, install the HPE MR type-o Gen11 storage controller (OROC).
E3.S drive bay numbering E3.S drive bay numbering
The 8 E3.S 32G x4 NVMe UBM5 E3C drive backplane option is supported.
For more information on the drive backplane description, see Drive backplane naming.
Drive backplane naming Drive backplane naming
This topic explains the features represented in the drive backplane naming. This naming convention was adopted starting in the HPE Gen11
server release. Your server might not support all the features listed in this topic. For server-specific support information, see the server
guides:
Drive backplane support, see Drive bay numbering.
Drive backplane cabling, see Storage cabling.
HPE ProLiant DL320 Gen11 Server Maintenance and Service Guide 206