When you mentioned not being detected by Unraid I assumed not detected by Linux, it's being detected by Unraid, it's in RAID mode and with a very old firmware, so it should be flashed to firmware 20.00.07.00 IT mode:
Dec 31 16:29:04 Tower kernel: mpt2sas_cm0: LSISAS2008: FWVersion(07.15.08.00), ChipRevision(0x03), BiosVersion(07.02.04.00)
Dec 31 16:29:04 Tower kernel: mpt2sas_cm0: Protocol=(Initiator,Target), Capabilities=(Raid,TLR,EEDP,Snapshot Buffer,Diag Trace Buffer,Task Set Full,NCQ)