Marvell 88NR2241

The Marvell 88NR2241 is not a flash controller but an intelligent NVMe switch, designed to aggregate multiple back-end NVMe SSD controllers behind a single host-facing PCIe interface. It is DRAM-less and adds RAID 0, RAID 1, and RAID 10 across the attached SSDs, along with features the underlying drives may not natively support, including multiple namespaces, NVMe reservations, and NVMe-MI management. This allows consumer-grade NVMe SSDs to present enterprise-class reliability and serviceability characteristics to the host.

In the WD Black AN1500, the 88NR2241 connects to two internal NVMe SSD controllers via PCIe x4 each and presents the combined storage to the host over a PCIe x8 interface in RAID 0, roughly doubling throughput compared to a single drive. The switch itself contributes minimal latency overhead by design.