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Black 16-bay rackmount NAS unit with front drive trays and rear dual power supplies

Synology Inc.

Synology Inc. RS4021xs+ 16-bay rackmount NAS 16GB DDR4

SKU CH-KTFG-FAM0Z MPN RS4021xs+

A 16-bay rackmount NAS with an 8-core 2.1 GHz Intel Xeon D-1541 processor, 16 GB DDR4 ECC memory, dual 10GbE and four 1GbE ports, supporting up to 288 TB raw capacity and expansion to 40 bays

  • Port RJ-452 x 10GbE + 4 x 1GbE
  • Port USB2 x USB 3.2 Gen 1
  • HDD Interface16 x SATA (16 x Bay)
  • Form Factor16-Bay
  • ProcessorIntel Xeon D-1541 8-core (16-thread) 2.1GHz
  • Installed Memory16GB DDR4

Model RS4021xs+

  • Handles massive workloads with 234698 random read IOPS
  • 16 drive bays expandable to 40 for growing storage needs
  • Dual 10GbE ports deliver high-speed network connectivity
  • Intel Xeon 8-core processor powers demanding multi-user services
  • 16GB ECC DDR4 memory scales to 64GB for reliability

16-bay rackmount NAS for data-intensive workloads

The RS4021xs+ is a 16-bay rackmount NAS powered by an Intel Xeon D-1541 8-core processor running at 2.1 GHz. It ships with 16 GB of DDR4 ECC memory expandable to 64 GB across four slots. The unit is designed for environments that require high throughput and compute capacity for many simultaneous users.

Sustained throughput with redundant power

Under continuous load the system delivers up to 234,698 4K random read IOPS and 6,258 MB/s sequential read performance. Dual redundant power supplies protect against a single PSU failure or accidental cord removal. Hot-swappable fans can be replaced without powering down the chassis, keeping services available during maintenance.

Sixteen drive bays with expansion headroom

Sixteen SATA bays accept drives from the Synology compatibility list; only Synology SAT5200 2.5" or SNV3500 series SSDs may be used for SSD cache. Two PCIe slots allow additional network or storage cards. An RX1217RP or RX1217 expansion unit can increase the total bay count to 40. The operating temperature range is 0 °C to 35 °C.

Highlights

  • Handles massive workloads with 234698 random read IOPS
  • 16 drive bays expandable to 40 for growing storage needs
  • Dual 10GbE ports deliver high-speed network connectivity
  • Intel Xeon 8-core processor powers demanding multi-user services
  • 16GB ECC DDR4 memory scales to 64GB for reliability

Specifications

BrandSynology
ModelRS4021xs+
Port RJ-452 x 10GbE + 4 x 1GbE
Port USB2 x USB 3.2 Gen 1
HDD Interface16 x SATA (16 x Bay)
Form Factor16-Bay
ProcessorIntel Xeon D-1541 8-core (16-thread) 2.1GHz
Installed Memory16GB DDR4
Max Memory Capacity64GB
Memory Slot4
Included HDD CapacityDiskless System
Max Capacity288TB
Drive CompatibilityOnly drives listed on the compatibility list can be used to create storage pools*
Only Synology SAT5200 2.5" or Synology SNV3500 series SSDs (sold reparately) can be used to create SSD caches**
* Check Synology compatibility list for supported drives.
** SSD cache can be enabled by using Synology SAT5200 2.5" SSDs or without occupying drive bays by installing Synology SNV3500 NVMe SSDs using M2D20 or E10M20-T1 adapter cards, sold separately.
RAIDRAID 0, 1, 5, 6, 10, JBOD, Synology RAID F1, Basic
Supported ProtocolsSMB, AFP, NFS, FTP, WebDAV, CalDAV, iSCSI, Telnet, SSH, SNMP, VPN (PPTP, OpenVPN, L2TP)
Power100 V to 240 V AC, 50/60 Hz, single phase
Power Consumption145.79 W (Access)
62.68 W (HDD Hibernation)
FeaturesAccelerated Performance
Up to 234,698 random read IOPS and 6,258 MB/s sequential read performance
Powerful Compute
Host multiple compute-intensive services with its 8-core Intel processor
Upgradability
Two PCIe expansion slots allow for M.2 NVMe cache adapters and high-bandwidth network cards
Redundant Power
Ensure business continuity with two redundant power supplies
On-demand Scalability
Supports up to 40 drive bays using two RX1217(RP)
UsageUltra high prerformance for large number of users
TemperatureOperating temperature: 0°C to 35°C (32°F to 95°F)
Storage temperature: -20°C to 60°C (-5°F to 140°F)
Humidity5% to 95% RH
Dimensions5.21" x 18.98" x 25.85"
Weight38.36 lbs.
Package Contents1 x RS4021xs+ main unit
1 x Quick Installation Guide
1 x Accessory pack
2 x AC power cords
Shipping weight22.97 kg
Package size889 × 635 × 298 mm

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Questions about this item

How much power does the RS4021xs+ draw when the drives are active versus when they are hibernating?

The unit consumes 145.79 W during access and drops to 62.68 W when the hard drives enter hibernation.

Which drive models are officially supported for storage pools and SSD cache on this unit?

Only drives on the Synology compatibility list may form storage pools; SSD cache requires Synology SAT5200 2.5" or SNV3500 series SSDs.

Can the RS4021xs+ be expanded with an RX1217RP expansion unit that I already own?

Yes, the RS4021xs+ supports up to 40 bays when connected to an RX1217RP or RX1217 expansion unit.

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