In the software-defined storage scenario, the local NVMe disk of the storage node is responsible for caching and hot data, but the motherboard often only has one or two M.2 slots. The mainstream solution for expansion is PCIe to M.2 expansion card. There are three steps to selecting a model, and many people make the wrong step in the first step.
Step 1: Confirm slot length and BIOS split capability
One x8 or x16 slot needs to carry multiple M.2 cards, provided that the BIOS supports PCIe channel splitting (bifurcation) into multiple x4s; without this capability, a four-port card can only light up one disk. Before purchasing a card, check the motherboard manual or consult the manufacturer to confirm support before deciding on the card type to avoid rework if the card does not light up upon arrival.
Step 2: Select cards according to the number and type of disk slots
- PCI-EX8 to 4-port M.2+4-port SATA expansion card: Accommodates both NVMe cache disks and SATA capacity disks, suitable for hot and cold stratification of a single node.
- PCI-EX16 to M.2 four-port expansion card (double-sided version): The disk slots are arranged on both sides of the card body, saving slots, and are suitable for nodes with high all-flash capacity requirements.
- PCI-EX4 to 2-port M.2+2-port SATA array card: Entry-level cache acceleration for small storage servers.
Step Three: Heat Dissipation and Asset Identification Leakage
Enterprise-level NVMe disks consume a lot of power for continuous writing, and stacking multiple disks can easily trigger temperature speed limits. It is recommended to choose products with a heat dissipation structure and ensure chassis air ducts. Each disk is marked with a slot and the corresponding OSD or volume number. The speed of troubleshooting when a faulty disk is replaced will be completely different.
EB-LINK's PCIe and M.2 expansion card series are available from stock. If you are not sure whether the motherboard supports splitting, you can call 0755-83179002 to confirm the motherboard model.