RackStation RS4021xs+

Enterprise NAS with built-in service continuity engineered for data-intensive applications.

Securing your business assets

The 16-bay RS4021xs+ provides solid data security and lightening-fast performance with over 234K 4K random read IOPS and 6,258 MB/s sequential read throughput1. Together with its 8-core processor, ECC memory, advanced snapshot technology, and built-in 10GbE connectivity, the RS4021xs+ can support large multi-user environments while handling data-intensive workloads.


Intel ®  Xeon ®  D-1541 8-core 2.1 GHz


Built-in dual-port 10GbE


16 GB ECC DDR4 Up to 64 GB


Up to 40 drive bays with RX1217(RP)

5-year warranty

At Synology, we are committed to product innovation and quality.

The RS4021xs+ is backed by a 5-year limited warranty that includes

technical support and hardware replacement services to maximize

your return on investment.

RackStation RS4021xs+

  • 1 Power button and indicator
  • 2 Alert Off Button
  • 3 Drive tray
  • 4 Drive status indicator
  • 5 PSU fan
  • 6 Power Port
  • 7 PSU Indicators & Alert Off Buttons
  • 8 Console port

  • 9 1GbE/10GbE RJ-45 Ports
  • 10 USB 3.2 Ports
  • 11 Expansion port
  • 12 PCIe expansion slot
  • 13 Reset button


  1. Performance testing conducted by Synology with 10GbE NICs installed. Actual results may vary depending on system configuration, testing methods, and other environmental variables. Check the performance page for additional details.
  2. Network adapter cards, expansion units, other PCIe add-in cards, and storage drives are sold separately. Refer to the compatibility list for compatible devices.
  3. SSD cache can be enabled by using compatible 2.5" SSDs or without occupying drive bays by installing Synology SNV3500 M.2 22110 NVMe SSDs using M2D20 or E10M20-T1 adapter cards, sold separately.
  4. Users have reported total data size reductions of more than 50% when backing up multiple systems with deduplication technology.
  5. Surveillance Station includes 2 free licenses. Connecting more cameras and devices requires additional licenses.