Synology RS4021xs+ 16-Bay Enterprise Rackmount NAS

At a Glance

• 16-bay 3U enterprise rackmount NAS
• Intel Xeon 8-core / 16-thread processor
• 16GB DDR4 ECC memory, expandable to 64GB
• Dual 10GbE + four 1GbE ports built in
• Expandable from 16 to 40 drive bays
• Dual PCIe expansion slots
• Redundant power supplies
• 5-Year Synology Hardware Warranty

Important: Storage drives and rack rails are not included.

Short Description

The Synology RS4021xs+ is a high-performance 16-bay enterprise rackmount NAS designed for large multi-user environments and data-intensive business workloads.

With Intel Xeon processing, 16GB ECC memory, dual built-in 10GbE networking, redundant power and expansion support for up to 40 drives, it provides a powerful platform for enterprise storage, backup, virtualisation and large surveillance deployments.

Why Choose This Synology

Power for Demanding Enterprise Workloads

An 8-core Intel Xeon processor and ECC memory provide the computing resources required for heavy file workloads, large user environments, backup and virtualisation storage.

Extensive Networking Built In

Two 10GbE ports and four additional 1GbE ports provide high-speed connectivity and flexible network redundancy without immediately requiring an expansion card.

Start with 16 Bays and Grow to 40

Two compatible RX1217 or RX1217RP expansion units can increase total drive capacity from 16 to a maximum of 40 bays.

Room for Further Expansion

Two PCIe Gen3 x8 expansion slots support selected Synology network and SSD-cache adapters for environments requiring additional bandwidth or storage acceleration.

Enterprise-Focused Resilience

ECC memory, redundant power and Synology High Availability support make the RS4021xs+ suitable for environments where access to critical data must be protected.

Best For

• Enterprise file storage
• Large multi-user environments
• Virtualisation storage
• Business backup and recovery
• Data-intensive applications
• High-speed 10GbE networks
• Large surveillance deployments
• High-availability environments
• Long-term storage growth

Product Description

The Synology RackStation RS4021xs+ is a 16-bay 3U enterprise NAS designed for organisations with demanding performance, capacity and availability requirements.

Its Intel Xeon D-1541 processor provides 8 cores and 16 threads, while 16GB DDR4 ECC memory is included as standard and can be expanded to 64GB.

Sixteen hot-swappable bays support compatible 3.5-inch SATA HDDs and 2.5-inch SATA SSDs.

Networking is extensive straight out of the box, with two built-in 10GbE RJ-45 ports and four 1GbE ports. Two PCIe Gen3 x8 slots provide additional flexibility for compatible network interfaces and SSD-cache adapters.

Up to two compatible RX1217 or RX1217RP expansion units can increase total storage capacity from 16 to 40 drive bays.

Redundant power supplies help protect against single PSU failure, while Synology High Availability provides an option for additional service continuity using a compatible paired system.

Synology DSM provides integrated tools for centralised file management, backup, collaboration, virtualisation storage, surveillance and data protection.

Storage drives are sold separately.

Key Features

• 16-bay 3U enterprise NAS
• Intel Xeon D-1541 processor
• 8 cores / 16 threads
• 16GB DDR4 ECC memory
• Expandable to 64GB
• Dual built-in 10GbE networking
• Four additional 1GbE ports
• Expandable to 40 drive bays
• Two PCIe Gen3 x8 slots
• SSD cache support
• Redundant power
• RAID F1 support
• Synology High Availability
• 5-year warranty

What Do I Need With This NAS?

Required

• Compatible storage drives

Optional Upgrades

• Additional ECC memory
• RX1217 or RX1217RP expansion units
• M.2 NVMe SSD cache
• Additional 10GbE or 25GbE networking
• RKS-02 sliding rail kit
• Additional Surveillance Station licences

Compatible Storage

Synology lists:

3.5-inch SATA HDD

• HAT5300 Enterprise Series

2.5-inch SATA SSD

• SAT5200 Enterprise Series

M.2 NVMe SSD Cache

Compatible Synology M.2 NVMe SSDs can be installed using supported M2D20 or E10M20-T1 adapters.

Compatibility Note: Exact storage compatibility is model-specific. Verify the exact drive against Synology's current RS4021xs+ Compatibility List before purchase.

Compatible Upgrades & Accessories

Increase Memory

• D4EC-2666-16G

Maximum system memory: 64GB

Expand Storage

• RX1217
• RX1217RP

Up to two expansion units can increase total drive capacity to 40 bays.

SSD Cache

• M2D20
• E10M20-T1

Expand Networking

• E25G30-F2
• E10G30-F2
• E10G30-T2
• E10G18-T1

Rack Installation

• RKS-02 Sliding Rail Kit

Surveillance Station

The RS4021xs+ includes 2 Surveillance Station device licences.

Synology supports up to 285 IP cameras at 1080p with H.265 under its specified test configuration.

Additional cameras require additional Synology Surveillance Device Licences.

Specifications

What’s in the Box

• Synology RS4021xs+ Main Unit × 1
• Accessory Pack × 1
• AC Power Cord × 2
• Quick Installation Guide × 1

Warranty

5-Year Synology Limited Hardware Warranty

Sustainability

• RoHS Compliant