[ MODEL IDENTIFICATION // RM21-308 ]
SilverStone RM21-308 2U hot-swap chassis
A 2U rack chassis with model-specific drive, PSU and expansion layouts. Match the enclosure revision, backplane and rail kit before installation.
MODEL NOTE: This record covers the RM21-308 only. Options, revision-dependent PSU support and installed bay modules may change fit; verify labels and the manufacturer manual before buying replacement parts.
Dimensions & fit specifications
| Rack units / external dimensions | 2U; 430 × 88.5 × 480 mm (W × H × D); body dimensions exclude installed rack rails, cables and rear service loop. |
|---|---|
| Motherboard compatibility | Micro-ATX (244 × 244 mm) and Mini-ITX (170 × 170 mm). |
| PSU / power compatibility | PS/2 ATX PSU up to 220 mm deep, or a compatible 2U single/redundant server PSU. PSU is not included. Verify connector and cable-exit clearance against the installed drive cage. |
| Drive bays / backplane | Eight 3.5-inch/2.5-inch hot-swap SAS/SATA bays on an 8-drive backplane using 2 × Mini-SAS SFF-8087 host connectors; two internal 2.5-inch mounts and one slim optical bay (12.7 mm). Confirm the fitted backplane and controller generation before cabling. |
| Riser / PCIe | Four low-profile PCI/PCIe positions. Card mounting requires a compatible low-profile layout; check the board slot location and any required riser against the exact assembly—no universal riser is implied. |
| Cooling / service clearances | Three 80 × 15 mm PWM fan positions; maximum CPU cooler height 68 mm. Allow additional rack depth beyond the 480 mm body for rails, power plugs, SAS leads and cable bend radius; keep the intake and exhaust unobstructed. |
Compatibility & service notes
The front hot-swap plane is an 8-bay SAS/SATA backplane, not eight direct motherboard ports. Match the controller cables to the installed SFF-8087 backplane revision. Rear access is needed for power and Mini-SAS leads; use a rack depth measurement that includes rail travel and cable service loop.
- Measure the complete installed depth: chassis, rack ears/slides, cable-management arm if fitted, connectors and cable bend radius.
- Maintain clear front intake and rear exhaust access; do not obstruct removable fan, drive, PSU or backplane service paths.
- Before hot-swap work, confirm the controller/backplane interface and follow the chassis manual’s power-down and ESD procedure.
Manufacturer sources
- SilverStone — RM21-308 product specificationsManufacturer page identifies the chassis and publishes fit, bay, PSU and cooling specifications.
- SilverStone — RM21-308 installation manual (PDF)Manufacturer installation guide for motherboard, PSU, drive and rack mounting.