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Synology 24Bay Expansion Kits (Rack Type)


Supports creating volumes across different units:

  • FS series: FS6400, FS3600, FS3400

Drive Bays: 24

Compatible Drive Type:

  • 2.5″ SAS HDD
  • 2.5″ SAS SSD
  • 2.5″ SATA SSD

Maximum Internal Raw Capacity:92.16 TB (3.84 TB drive x 24) (Capacity may vary by RAID types)

SAS IN-port: 1

SAS OUT-port: 1

Power Supply Unit / Adapter: 500W

Packaging Content:

  • Main Unit x 1
  • Accessory Pack x 1
  • AC Power Cord x 2
  • Expansion Cable: Mini-SAS-HD X 1
  • Quick Installation Guide x 1


24-bay 2.5″ expansion unit for Synology FlashStation

Expand your Synology FlashStation1 with Expansion Unit FX2421 for 24 additional 2.5” drive bays whenever needed. Without additional software configuration, FX2421 is immediately ready for use when connected to Synology FlashStation. FX2421 expansion units can also be used as a dedicated and rapidly accessible local backup destination.

Expand FlashStation with Synology SAT5200 SSD

Synology enterprise-grade SAT5200 SATA SSD, developed in tandem with FX2421, provides proven interoperability and high reliability through rigorous validation and compatibility testing with Synology expansion units. Combine SAT5200 drives with Synology FlashStation and FX2421 for a highly reliable and integrated storage setup, and receive long-term Synology updates and support.

High-performance data transmission

The high-speed expansion cable provided with FX2421 enables high bandwidth connectivity for maximum data throughput between your Synology FlashStation and Expansion Unit. Drives in FX2421 operate with minimum data latency, as if installed directly on your Synology FlashStation, allowing you to take advantage of high SSD I/O performance.

High-reliability design, easy hardware setup

The FX2421 is a highly reliable and thoroughly tested expansion unit that comes with hot-swappable drive trays and modularized components. Redundant power supplies and system fans can be replaced with ease to ensure maximum service uptime. The optional RKS1317 sliding rail kit provides fast rack fixing lock support for quick and secure rack cabinet installation.