HPE ProLiant DL320 Gen11 Maintenance And Service Manual page 200

Amber/blue LED—Managed by the drive backplane in conjunction with the storage controller and is used to indicate drive status.
Green LED—Managed by the drive itself and indicates the drive activity.
LFF low-profile drive carrier LFF low-profile drive carrier
The LFF low-profile drive carrier supports hot-plug SAS or SATA.
SFF basic drive carrier SFF basic drive carrier
The SFF basic drive carrier supports hot-plug SAS, SATA, or U.3 NVMe .
HPE ProLiant DL320 Gen11 Server Maintenance and Service Guide 200