How many hot-swap drive bays does this server have?

The server has 12 hot-swap 3.5" SATA drive bays and 4 hot-swap 2.5" NVMe (PCIe4.0 x4) drive bays.

What type of processors are supported by the ASRock Rack Server Storage Barebone 1U12L4E-GENOA/2Q?

It supports AMD EPYC™ 9005*/9004 processors with AMD 3D V-Cache™ Technology and 97x4 series processors.

double click image to zoom in

ASRock Rack Server Storage Barebone 1U12L4E-GENOA/2Q Single Socket SP5 (LGA 6096), AMD EPYC™ 9005*/9004 12 SATA Dual SFP28 (25GbE)

1U Rackmount with 1+1, 1000W Slim RPSU
Single Socket SP5 (LGA 6096), supports AMD EPYC™ 9005*/9004 (with AMD 3D V-Cache™ Technology) and 97x4 series processors
12 DIMM slots (1DPC), supports DDR5 RDIMM, RDIMM-3DS
12 Hot-swap 3.5" SATA drive bays
4 Hot-swap 2.5" NVMe (PCIe4.0 x4) drive bays
1 FHHL PCIe5.0 x16, 1 HHHL PCIe5.0 x16
1 OCP NIC 3.0 (PCIe5.0 x16)
2 M-key (PCIe5.0 x4 or 4 SATA 6Gb/s)
2 SFP28 (25GbE) by Broadcom BCM57414
Remote management (IPMI)