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)
• Genuine Synology memory modules must be installed to ensure system compatibility and reliability

Compatible drive types

• 16 x 3.5″ or 2.5″ SATA HDD/SSD (drives not included)
• Only 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

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 RJ45
• 2 x 10GbE RJ45

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 cache

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

• 0°C to 35°C (32°F to 95°F)

Storage temperature

• -20°C to 60°C (-5°F to 140°F)

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+, exFAT

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 TB
• Maximum system snapshots: 65,536
• Maximum internal volumes: 256

SSD cache

• Read/write cache support
• 2.5″ SATA SSD support
• M.2 NVMe SSD support 8

File sharing capabilities

• Maximum local user accounts: 16,000
• Maximum local groups: 512
• Maximum shared folders: 512
• Maximum concurrent SMB/NFS/AFP/FTP connections: 4,000

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 (customisable 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, Ceský

File Server & Synchronization

Drive

• Synchronizes files across Windows, macOS, Linux, Android and iOS. The built-in cross-platform portal allows access to data anytime and anywhere.
  • Maximum number of hosted files: 5,000,000
  • Maximum number of concurrent connections for PC clients: 2,000

File Station

• Provides virtual drives, remote folders, Windows ACL editor, compression/extraction of archived files, bandwidth control for specific users/groups, creation of sharing links, and transfer logs.

FTP Server

• Supports bandwidth control for TCP connections, custom FTP passive port ranges, anonymous FTP, FTP over TLS/SSL and SFTP protocols, network booting with TFTP and PXE support, and transfer logs.

Presto File Server

• Enables high-speed data transfer over WAN through the exclusive SITA technology between Synology NAS and desktop.

Cloud Sync

• Offers one or two-way synchronisation with public cloud storage providers including Alibaba Cloud OSS, Amazon S3-compatible storage, Backblaze B2, Baidu Cloud, Box, Dropbox, Google Cloud Storage, Google Drive, hubiC, MegaDisk, Microsoft OneDrive, OpenStack Swift-compatible storage, Tencent COS, WebDAV servers and Yandex Disk.

Universal Search

• Enables global search of applications and files.

iSCSI Storage & Virtualization

iSCSI Manager

• Maximum iSCSI targets: 256
• Maximum iSCSI LUNs: 512
• iSCSI LUN clone/snapshot support

Virtual Machine Manager

• Deploys and runs virtual machines on the Synology NAS, including Windows, Linux, and Virtual DSM.

Data Protection & Backup Solution

Hyper Backup

• Supports local backup, network backup, and data backup to public clouds.

Backup tools

• DSM configuration backup, macOS Time Machine support, Synology Drive Client desktop application
• Shared folder sync supports a maximum of 32 tasks

Snapshot Replication

• Maximum number of snapshots for shared folders: 1,024
• Maximum number of replications: 64

Synology High Availability

• Reduces service downtime by combining two identical NAS into a high-availability cluster.

Active Backup for G Suite

• Supports backup and restoration of Google Workspace My Drive, Team Drive, Gmail, Contacts, and Calendar.

Active Backup for Microsoft 365

• Supports backup and restoration of Microsoft 365 OneDrive for Business, mail, contacts, and calendar.

Active Backup for Business

• An all-in-one backup solution designed for heterogeneous business IT environments. It enables IT admins to remotely manage and protect PCs, servers, and VMs from one centralised console.

Productivity & Collaboration

Collaboration tools

• Users can collaborate through the instant messaging service Synology Chat, the online editor Synology Office, and the scheduling assistant Synology Calendar.
  • Maximum users for Chat: 6,000
  • Maximum users for Office: 3,000
  • Calendar supports CalDAV and access via mobile devices

Note Station

• A note taking platform that supports rich text, note organisation and versioning, encryption, sharing, media embedding, and attachments.

Synology MailPlus Server

• A secure, reliable, and private mail solution featuring high-availability, load balancing, security, and filtering.

Synology MailPlus

• An intuitive webmail interface for Synology MailPlus Server with customisable mail labels, filters, and user interface.

Multimedia

Moments

• A feature-rich photo management application that includes AI-powered album creation from facial and subject recognition, photo editing and sharing capabilities, similar photo detection for duplicate management, auto-editing functions such as colour correction and angle adjustments, and auto-selection of the best shots. Mobile applications are available on iOS and Android devices.

Other packages

• Video Station, Photo Station, Audio Station, iTunes Server

Surveillance

Surveillance Station

• Maximum IP cameras: 90, for a total of 2,700 FPS at 720p (H.264).

All-in-One Servers

Synology Directory Server

• Provides a flexible and cost-effective domain controller solution.

Central Management System

• Provides a single interface to manage and monitor multiple Synology NAS.

VPN Server

• Maximum connections: 40
• Supported VPN protocols: PPTP, OpenVPN, L2TP/IPSec

Mail Server

• Supported Mail Server protocols: POP3, SMTP, IMAP
• LDAP/AD account support

Mail Station

• A webmail interface for Mail Server to receive emails from multiple POP3 mailboxes and SMTP servers.

Web Station

• Enables hosting for up to 30 websites with support for PHP/MariaDB and 3rd-party applications.

Other packages

• DNS Server, RADIUS Server, Log Centre

Others

Storage Analyser

• Displays volume and quota usage, total size of files, volume usage and trends based on past usage, size of shared folders, large files, most recently modified files, and least recently accessed files.

Antivirus Essential

• Provides full system scans, scheduled scans, white list customization, and auto-update of virus definitions.

iOS/Android applications

• Synology Drive, Synology MailPlus, Synology Chat, Synology LiveCam, Moments, DS audio, DS photo, DS video, DS cam, DS file, DS finder, DS note

Other packages

• Additional 3rd-party packages are available in the Package Centre.

Environment and Packaging

Environment safety

• RoHS compliant

Package contents

• 1 x Synology RS4021xs+ enclosure
• 1 x Quick Installation Guide
• 1 x Accessory pack
• 2 x AC power cords