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€ 5759,–
€ 4759,50 ex. 21% VAT

Synology RS4021xs+

in stock (1 unit) | order today = shipped on morgen
  • RS4021xs+ is a powerful 16-bay 3U RackStation
  • 16 GB DDR4 ECC UDIMM (expandable up to 64 GB)
  • Expandable to 40 bays using two Synology RX1217(RP)
  • Intel Xeon D-1541 8-core (16-thread) 2.1 GHz,
When ordering NAS + HDD's you get free assembly!

Product Description RS4021xs+

Click here for an overview of all compatible harddrives.

We recommend that you only install drives that are in the compatibility list of your device. We,, cannot provide technical support for devices that use unsupported components.

Synology RackStation RS4021xs+ is a powerful 16-bay 3U storage solution designed for high throughput and data integrity, made with built-in redundant power. Equipped with an 8-core processor and upgradable to 64 GB memory, the RS4021xs+ is capable of hosting demanding services involving virtualization, mail, office collaboration, and surveillance, to meet the unique requirements of enterprise environments.

Built to Handle Intensive Workloads
Synology RackStation RS4021xs+ is built to deliver exceptional performance, flexibility, and scalability for demanding enterprise environments. 

  • Up to 234,698 4K random read IOPS and 6,258 MB/s sequential read performance for demanding workloads1 
  • Featuring 16 drive bays supporting both SATA HDD/SSD 2.5/3.5 inch drives, expandable to 40 bays using two Synology RX1217(RP) expansion units 

Optimized for Data Protection and Integrity
Powered by Synology DSM, our unified datamanagement operating system, and built upon the Btrfs file system, data stored on the RS4021xs+ is safely guarded by modern data protection technologies. 

  • Advanced snapshots technology provides schedulable and near-instantaneous data protection of shared folders and LUNs 
  • File and folder-level data restoration enables restoration of specific files or folders 
  • Flexible storage quota system helps admins effortlessly manage available space by specifying storage limits for shared folders 
  • File self-healing detects and recovers corrupted files using mirrored metadata and RAID configurations
  • Inline compression compresses data before writing it to the drive, reducing write commands and optimizing storage space

Virtualization and Certified Storage
DSM streamlines the provisioning and management of storage for virtual machines (VM). Certified for VMware vSphere, Microsoft Hyper-V, Citrix XenServer, and OpenStack, it integrates with your virtualization platform of choice through iSCSI or NFS protocols. Install Synology Storage Console on VMware or Windows platforms for additional management convenience and functionality right in the hypervisor. 

Synology Virtual Machine Manager (VMM) is a hosted hypervisor for virtual machines running Windows, Linux, or virtualized versions of DSM with recovery mechanisms that ensure data protection on each VM.

Data Backup Solutions for IT Infrastructure
Synology Active Backup Suite is a collection of license-free backup solutions built to protect Windows PCs and servers, VMs, other file servers, and cloud-based storage. 

  • Active Backup for Business (ABB) consolidates backup tasks for physical and virtual environments and enables rapid restoration of files, entire physical machines, and VMs. 
  • Active Backup for G Suite enables backup of Google Workspace data including Gmail, Contacts, Calendar, and Drive.
  • Active Backup for Microsoft 365 enables backup of Microsoft 365 data including OneDrive for Business, SharePoint Online, emails, contacts, and calendar.

On-Premises Collaboration
 Synology's collaboration suite is a private SaaS for file sharing, concurrent document editing, emails, instant messaging, and more. By leveraging a private cloud infrastructure, it ensures data ownership while multilayered security enables secure multi-platform access. 

  • Synology Drive allows data access, synchronization, on-demand file restoration, and backup. 
  • Synology MailPlus6 provides a secure, reliable, and private email server. 
  • Synology Chat brings teams together through instant multi-platform communication. 
  • Synology Calendar helps teams keep track of what is most important with convenient calendar sharing and scheduling.

Private Video Surveillance
With Synology Surveillance Station, the RS4021xs+ becomes a powerful Network Video Recorder solution with support for up to 90 IP cameras. 

  • 7,600+ supported camera models 
  • ONVIF support to prevent vendor lock-in 
  • Private, subscription-free storage of the recordings 
  • Access through web browser, dedicated desktop clients, or mobile app 
  • Event-based rules to trigger specific actions 
  • Email, SMS, or push notification systems

For more information, please visit this products webpage.


  • Synology RS4021xs+ with 16 x 4TB Seagate Exos 7E8 SATA HDD ST4000NM002A
    ordered on demand | € 9486,96
    € 7840,46 ex. 21% VAT
  • Synology RS4021xs+ with 16 x 8TB Synology 3.5 Inch SATA HDD
    in stock | € 11166,99
    € 9228,92 ex. 21% VAT
  • Synology RS4021xs+ with 16 x 12TB Synology 3.5 Inch SATA HDD
    in stock | € 14079,00
    € 11635,54 ex. 21% VAT


CPU Intel Xeon D-1541 8-core (16-thread) 2.1 GHz, Turbo Boost up to 2.7 GHz
RAM 8 GB DDR4 ECC UDIMM (expandable up to 64 GB)
Nr. of HDD slots 16 slots
Harddisk interface 2,5'' SATA III, 3,5'' SATA III
External interface 2 x USB 3.2, 2 x Expansion port
LAN 4 x 1 Gigabit, 2 x 10 Gigabit
Encryption Hardware based
Link aggregation No
Redundant power supply Yes
Wireless No
Package content 1 x RS4021xs+ main unit
1 x Quick Installation Guide
1 x Accessory pack
2 x AC power cords
Warranty 5 year
EAN Code 4711174724086

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CPU Intel Xeon D-1541 8-core (16-thread) 2.1 GHz, Turbo Boost up to 2.7 GHz
Hardware encryption engine Yes (AES-NI)
Memory 16 GB DDR4 ECC UDIMM (expandable up to 64 GB)
Compatible drive types 16 x 3.5 or 2.5 inch SATA HDD/SSD (drives not included)
Hot swappable drive Yes
External ports 2 x USB 3.2 Gen 1 ports
2 x Expansion ports (Infiniband)
Form factor Rackmount 3U
Size (HxWxD) 132.3 x 482 x 656.5 mm (with server handles)
Weight 17.4 kg
LAN ports 4 x 1GbE RJ-45
2 x 10GbE RJ-45
Wake on LAN/WAN Yes
PCIe 3.0 slots 2 x 8-lane x8 slots
Supports network interface cards and M.2 NVMe SSD adapter cards for SSD cache8
Scheduled power on/off Yes
System fans 3 x (80 x 80 x 32 mm)
AC input power voltage 100 V to 240 V AC
Power frequency 50/60 Hz, single phase
Operating temperature 0C to 35C
Storage temperature -20C to 60C
Relative humidity 5% to 95% RH
Maximum operating altitude 5,000 m (16,400 ft)
General DSM Specification
Networking protocols SMB, AFP, NFS, FTP, WebDAV, CalDAV, iSCSI, Telnet, SSH, SNMP, VPN (PPTP, OpenVPN™, L2TP)
File systems Internal: Btrfs, ext4
External: Btrfs, ext4, ext3, FAT32, NTFS, HFS+, exFAT9
Supported RAID types Synology RAID F1, Basic, JBOD, RAID 0, RAID 1, RAID 5, RAID 6, RAID 10
Storage management Maximum single volume size: 108/200 TB10
Maximum system snapshots: 65,53611
Maximum internal volumes: 256
SSD cache Read/write cache support
2.5" SATA SSD support
M.2 NVMe SSD support8
File sharing capabilities Maximum local user accounts: 16,000
Maximum local groups: 512
Maximum shared folders: 512
Maximum concurrent SMB/NFS/AFP/FTP connections: 4,00012
Privileges Windows Access Control List (ACL), application privileges
Directory services Connects with Windows AD/LDAP servers enabling domain users to login via SMB/NFS/AFP/FTP/File Station using their existing credentials.
Virtualization VMware vSphere 6.5, Microsoft Hyper-V, Citrix, OpenStack
Security Firewall, shared folder encryption, SMB encryption, FTP over SSL/TLS, SFTP, rsync over SSH, login auto block, Let's Encrypt support, HTTPS (customizable cipher suite)
Supported clients Windows 7 onwards, macOS 10.12 onwards
Supported browsers Chrome, Firefox, Edge, Internet Explorer 10 onwards, Safari 10 onwards, Safari (iOS 10 onwards), Chrome (Android 6.0 onwards) on tablets
Interface languages English, Deutsch, Français, Italiano, Español, Dansk, Norsk, Svensk, Nederlands, ???????, Polski, Magyar, Português do Brasil, Português Europeu, Türkçe, ?eský

Did you notice a wrong specification? Please let us know.

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