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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.
Compute
Intel® Xeon® D-1541 8-core 2.1 GHz
Networking
Built-in dual-port 10GbE
Memory
16 GB ECC DDR4 Up to 64 GB
Scalability
Up to 40 drive bays with RX1217(RP)
Engineered for service continuity
The RS4021xs+ ensures mission-critical data is always available, enabling businesses to deliver the best results, even in the face of disaster.
Redundant power
Dual PSUs provide protection against a PSU failure or accidental cord removal while hot-swappable fans can be replaced without powering down the system.
Maximize service availability
Synology High Availability (SHA) pairs two identical units together creating an active-passive cluster with minute-level failover.
Next-generation file system
Btrfs prevents data corruption and reduces maintenance overheads with advanced storage technologies and optimized snapshots.
Customized to your business
The RS4021xs+ includes two PCIe slots for performance, networking, and storage upgrades, enabling it to adapt to any business environment2.
Double bandwidth
Upgrade network speeds by double or more with Synology's range of 10Gbe NICs.
SSD cache3
Boost read/write IOPS by up to 16 times by enabling SSD cache with our Synology M.2 NVMe adapter cards and SNV3500 SSDs, or by installing one or more 2.5” SAT5200 SSDs.
Storage expansion
Quickly and easily scale up to 40 drives with two RX1217(RP) expansion units.
The ultimate backup solutions — license-free
Keep disaster at bay
Hyper Backup
A comprehensive backup and recovery solution for securing data stored on Synology servers. Backup data locally, to another Synology device, rsync server, or cloud-based storage such as Google Drive, Dropbox, S3-compatible destinations, and Synology C2. Deduplication4, integrity checks, and incremental transfer technology reduce bandwidth and storage used.
Snapshot Replication
Easily schedule flexible point-in-time backups of shared folders and iSCSI LUNs with an RPO as low as 5 minutes and recovery in seconds. Set up replication and failover to other Synology storage systems for fast RTOs and minimal service disruption.
Backup your entire IT infrastructure
Active Backup Suite
Enables administrators to easily backup the entire IT infrastructure to their NAS, including Windows & Linux workstations and servers, file servers, VMware and Hyper-V virtual machines, and Microsoft 365 and Google Workspace accounts. Backups benefit from deduplication, multiversioning, and optimizations to reduce bandwidth and storage used.
Storage for virtualization
Synology iSCSI storage supports mainstream virtualization solutions with an easy management interface to enhance usability. VMware vSphere 6.5 and VAAI integration helps offload storage operations. Windows Offloaded Data Transfer (ODX) speeds up data transfer. OpenStack Cinder support turns your Synology NAS into a block-based storage component. Additionally, Synology Storage Console enables even more simplified storage provisioning and management options in VMware and Windows environments.
All-in-one surveillance solution
Synology Surveillance Station transforms the RS4021xs+ into a feature-packed Network Video Recorder solution. Support for up to 90 IP cameras5 and video analytics such as motion detection, no idle zone, foreign object detection, and anomaly detection cater to the most common surveillance scenarios.
Secure and private
AES-256 encryption keeps locally-stored footage secure.
Access from anywhere, anytime
Access recordings and live streams whenever you want using a web browser, desktop client, or the DS cam mobile app.
Real-time alerts
Email, SMS, or push notifications alert you when incidents occur or predefined conditions are met.
Works best with Synology drives
Engineered to handle intensive 24/7 workloads, Synology drives consistently deliver top-grade performance.
SATA
3.5” HDD HAT5300
2.5” SSD SAT5200
NVMe
M.2 SSD SNV3000
Powered by Synology DiskStation Manager
The RS4021xs+ runs Synology DiskStation Manager (DSM), the web-based operating system equipped with powerful applications and services for business.
Central Management System
Conveniently manage your fleet of Synology NAS from a centralized console.
Synology Drive
Instantly access your NAS files across multiple devices whenever you want, wherever you are.
Collaboration Suite
Satisfy all team collaboration needs behind the safety of your own private cloud with Synology Office, Calendar, and Chat.
Virtual Machine Manager
Run various operating systems in isolated sandboxes. Seamlessly clone, store, and migrate virtual machines.
Security
Secure data with comprehensive built-in security tools to protect your devices against evolving threats.
Public Cloud Integration
Back up and synchronize data easily between public cloud accounts and your NAS.
RackStation® RS4021xs+
1 Power button and indicator
2 Beep 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.
2. Network adapter cards, expansion units, other PCIe add-in cards, and storage drives are sold separately.
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.