DiskStation DS1621xs+
DiskStation DS1621xs+
On-premises cloud solution built for performance
High-end scalable NAS in desktop form factor
DS1621xs+ is a high-end NAS with server-class performance in a 6-bay desktop form factor. The built-in M.2 SSD cache slots, 10GbE port, expandable memory, and scalable storage design allow you to boost the performance of your NAS, making it ideal for small and medium-sized businesses that need an efficient and space-saving storage solution.

CPU
Intel® Xeon D-1527 4-core 2.2 GHz

Memory
8 GB DDR4 ECC SODIMM, up to 32 GB

High Performance
Over 3,100 MB/s sequential read

Scalability
Up to 16 drives with DX5171

5-year warranty
At Synology, we are committed to product innovation and quality. Synology guarantees a robust and reliable data management experience with a 5-year limited warranty, providing responsive technical support and hardware replacement services to maximize your return on investment.
Ultimate Backup Solution
DS1621xs+ integrates various backup applications into an intuitive user interface, offering durable storage technologies to safeguard your valuable data on any device.

Active Backup for Business
Centralize backup tasks for VMware, Windows, and file servers. Restore whatever you want fast and reliably when needed.
Learn more

Hyper Backup
Comprehensively back up your data to a local shared folder, an external device, another Synology NAS, an rsync server, or a public cloud to ensure data safety.
Learn more

Drive Package
Safeguard your computer with Synology Drive Client. Effortlessly perform real-time data backups and point-in-time file recovery.
Learn more

Active Backup for
Microsoft 365 / Google Workspace
Protect corporate data stored on the cloud. On-premise backup solution with a centralized dashboard. Optimize storage efficiency with single instancing and block-level deduplication technology.
Microsoft 365Google Workspace
Real-time collaboration on your private cloud
Synology Office is a collaboration package combining the convenience and usability of the public cloud with private cloud privacy and security. It enables seamless collaboration on documents and spreadsheets in a protected environment. Learn more
Virtual Machine Manager
Sandbox new software , manage resources using a single interface, and increase deployment flexibility with Synology Virtual Machine Manager. Run Windows, Linux, and Virtual DSM instances on your Synology NAS in just a few steps. Learn more
Snapshots for virtual machines
Clone and restore complete virtual machines within seconds.
Live migration
Seamlessly migrate virtual machines from one Synology NAS to another.
Multi-tenant environment
Create multiple isolated virtual machines for business units or departments.
Powered by Synology DiskStation Manager
Central Management System
Conveniently manage your fleet of Synology NAS from a centralized console.
Learn moreSynology MailPlus
Secure, reliable, and private mail server solution with an intuitive and modern mail client.
Learn moreSynology High Availability
Seamless transition between clustered servers in the event of a server failure to minimize the impact on applications.
Learn moreSecurity
Secure data with comprehensive built-in security tools to protect your devices against evolving threats.
Learn moreSynology Drive
Instantly access your NAS files across multiple devices whenever you want, wherever you are.
Learn moreSurveillance Station
Complete surveillance solution for recording, monitoring, and management.
Learn more

- 1 Status indicator
- 2 Alert indicator
- 3 Power button and indicator
- 4 LAN indicator
- 5 Drive status indicator
- 6 Drive tray
- 7 Drive tray lock
- 8 USB 3.0 port
- 9 System fan
- 10 Power port
- 11 Kensington Security Slot
- 12 10GbE RJ-45 port
- 13 1GbE RJ-45 port
- 14 Reset button
- 15 Expansion port
- 16 PCIe expansion slot
Notes:
- DS1621xs+ can be scaled up to 16 drives with 2 x DX517. Synology expansion units are sold separately.
Hardware Specifications |
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CPU |
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CPU |
CPU Model | Intel Xeon D-1527 |
CPU Quantity | 1 | |
CPU Architecture | 64-bit | |
CPU Frequency | 4-core 2.2 (base) / 2.7 (turbo) GHz | |
Hardware Encryption Engine (AES-NI) | ||
Memory |
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Memory |
System Memory | 8 GB DDR4 ECC SODIMM |
Memory Module Pre-installed | 8 GB (8 GB x 1) | |
Total Memory Slots | 2 | |
Maximum Memory Capacity | 32 GB (16 GB x 2) | |
Notes |
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Storage |
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Storage |
Drive Bays | 6 |
Maximum Drive Bays with Expansion Unit | 16 (DX517 x 2) | |
M.2 Drive Slots | 2 (NVMe) | |
Compatible Drive Type* (See all supported drives) |
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Maximum Single Volume Size* |
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Hot Swappable Drive | ||
Notes |
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External Ports |
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External Ports |
RJ-45 1GbE LAN Port | 2 (with Link Aggregation / Failover support) |
RJ-45 10GbE LAN Port | 1 | |
USB 3.2 Gen 1 Port* | 3 | |
eSATA Port | 2 | |
Notes | The USB 3.0 standard was renamed to USB 3.2 Gen 1 by the USB Implementers Forum (USB-IF) in 2019. | |
PCIe |
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PCIe |
PCIe Expansion | 1 x Gen3 x8 slot (x8 link) |
File System |
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File System |
Internal Drives |
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External Drives |
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Notes | exFAT Access is purchased separately in Package Center. | |
Appearance |
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Appearance |
Size (Height x Width x Depth) | 166 mm x 282 mm x 243 mm |
Weight | 5.3 kg | |
Others |
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Others |
System Fan | 92 mm x 92 mm x 2 pcs |
Fan Speed Mode |
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Easy Replacement System Fan | ||
Brightness Adjustable Front LED Indicators | ||
Power Recovery | ||
Noise Level* | 25.2 dB(A) | |
Scheduled Power On / Off | ||
Wake on LAN / WAN | ||
Power Supply Unit / Adapter | 250 W | |
AC Input Power Voltage | 100 V to 240 V AC | |
Power Frequency | 50/60 Hz, Single Phase | |
Power Consumption* |
62.85 W (Access) 34.26 W (HDD Hibernation) |
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British Thermal Unit |
214.45 BTU/hr (Access) 116.89 BTU/hr (HDD Hibernation) |
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Notes |
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Temperature |
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Temperature |
Operating Temperature | 0°C to 40°C (32°F to 104°F) |
Storage Temperature | -20°C to 60°C (-5°F to 140°F) | |
Relative Humidity | 5% to 95% RH | |
Certification |
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Certification |
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Warranty |
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Warranty |
5 Years | |
Notes | The warranty period starts from the purchase date as stated on your purchase receipt. (Learn more) | |
Environment |
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Environment |
RoHS Compliant | |
Packaging Content |
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Packaging Content |
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Optional Accessories |
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Optional Accessories |
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Notes | All memory modules will operate at the maximum frequency specified by the CPU manufacturer. |
DSM Specifications |
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Storage Management |
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Storage Management |
Maximum Internal Volume Number | 256 |
SSD Read / Write Cache (White Paper) | ||
SSD TRIM | ||
RAID Group | ||
Supported RAID Type |
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RAID Migration |
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Volume Expansion with Larger HDDs |
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Volume Expansion by Adding a HDD |
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Global Hot Spare Supported RAID Type |
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File Services |
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File Services |
File Protocol | SMB/AFP/NFS/FTP/WebDAV |
Maximum Concurrent SMB/AFP/FTP Connections | 2,000 | |
Maximum Concurrent SMB/AFP/FTP Connections (with RAM expansion) | 8,000 | |
Windows Access Control List (ACL) Integration | ||
NFS Kerberos Authentication | ||
Notes |
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Account & Shared Folder |
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Account & Shared Folder |
Maximum Local User Accounts | 16,000 |
Maximum Local Groups | 512 | |
Maximum Shared Folder | 512 | |
Maximum Shared Folder Sync Tasks | 32 | |
High Availability |
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High Availability |
Synology High Availability | |
Log Center |
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Log Center |
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Syslog Events per Second | 1,500 | |
Virtualization |
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Virtualization |
VMware vSphere with VAAI | |
Windows Server 2016 | ||
Windows Server 2019 | ||
Citrix Ready | ||
OpenStack | ||
General Specifications |
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General Specifications |
Networking Protocols | SMB1 (CIFS), SMB2, SMB3, NFSv3, NFSv4, NFSv4.1, NFS Kerberized sessions, iSCSI, HTTP, HTTPs, FTP, SNMP, LDAP, CalDAV |
Supported Browsers |
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Supported Language | English, Deutsch, Français, Italiano, Español, Dansk, Norsk, Svenska, Nederlands, Русский, Polski, Magyar, Português do Brasil, Português Europeu, Türkçe, Český, ภาษาไทย, 日本語, 한국어, 繁體中文, 简体中文 | |
Add-on Packages view the complete package list |
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Antivirus by McAfee (Trial) |
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Antivirus by McAfee (Trial) |
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Central Management System |
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Central Management System |
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Synology Chat |
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Synology Chat |
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Maximum Users | 4,000 | |
Notes |
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Document Viewer |
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Document Viewer |
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Download Station |
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Download Station |
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Maximum Concurrent Download Tasks | 80 | |
exFAT Access (Optional) |
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exFAT Access (Optional) |
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iSCSI Manager |
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iSCSI Manager |
Maximum iSCSI Target Number | 256 |
Maximum iSCSI LUN | 512 | |
iSCSI LUN Clone/Snapshot, Windows ODX | ||
Synology MailPlus / MailPlus Server |
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Synology MailPlus / MailPlus Server |
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Free Email Accounts | 5 (Licenses required for additional accounts) | |
Maximum Number of Concurrent Users | 450 | |
Maximum Server Performance | 3,363,000 emails per day, approx. 102GB | |
Notes |
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Media Server |
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Media Server |
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DLNA Compliance | ||
Moments |
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Moments |
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Facial Recognition | ||
Subject Recognition | ||
Auto Color & Rotate | ||
Moments Select | ||
Snapshot Replication |
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Snapshot Replication |
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Maximum Snapshots per Shared Folder | 1,024 | |
Maximum of System Snapshots | 65,536 | |
Surveillance Station |
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Surveillance Station |
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Maximum IP cam (Licenses required) | 75 (including 2 Free License) (See All Supported IP Cameras) | |
Total FPS (H.264) |
2250 FPS @ 720p (1280x720) 1050 FPS @ 1080p (1920x1080) 600 FPS @ 3M (2048x1536) 400 FPS @ 5M (2591x1944) 280 FPS @ 4K (3840x2160) |
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Total FPS (H.265) |
2250 FPS @ 720p (1280x720) 2250 FPS @ 1080p (1920x1080) 1125 FPS @ 3M (2048x1536) 700 FPS @ 5M (2591x1944) 490 FPS @ 4K (3840x2160) |
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Notes |
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Synology Drive |
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Synology Drive |
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Recommended Number of Hosted Files | 3,000,000 (applies to files indexed or hosted by Synology Drive. For file access through other standard protocols, refer to the File Services section above) | |
Recommended Number of Concurrent Sync Clients | 900 (the number of connections that can be maintained when the recommended number of hosted files was reached) | |
Notes |
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Synology Office |
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Synology Office |
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Maximum Users | 2,900 | |
Notes |
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Video Station |
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Video Station |
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Virtual Machine Manager |
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Virtual Machine Manager |
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Recommended Virtual Machine Instances | 8 (Learn more) | |
Recommended Virtual DSM Number (Licenses required) | 8 (including 1 Free License) | |
Notes | The specifications vary depending on system configuration and memory size. | |
VPN Server |
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VPN Server |
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Maximum Connections | 40 |
Notes:
- Model specifications are subject to change without prior notice.
- The figures are based on Synology internal testing. Each performance test is done individually. No other services or applications are processed at the same time.
- The actual performance may be lower than lab testing figure due to differences in server configuration, deployment, and the number of active operations.
- If usage requirements exceed the specifications above, please contact our regional partners for professional advice.