On-premises cloud solution built for performance
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.
Intel® Xeon D-1527 4-core 2.2 GHz
8 GB DDR4 ECC SODIMM, up to 32 GB
Over 3,100 MB/s sequential read
Up to 16 drives with DX5171
DS1621xs+ integrates various backup applications into an intuitive user interface, offering durable storage technologies to safeguard your valuable data on any device. Learn more
Centralize backup tasks for VMware, Windows, and file servers. Restore whatever you want fast and reliably when needed.
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.
Safeguard your computer with Synology Drive Client. Effortlessly perform real-time data backups and point-in-time file recovery.
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.
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
Real-time collaboration on the same online documents to boost productivity,
Instant communication on Synology Chat during the editing of documents or spreadsheets
Version control for you to navigate all the changes and retrieve previous versions with just a click
Real-time collaboration on the same online documents to boost productivity,
Instant communication on Synology Chat during the editing of documents or spreadsheets
Version control for you to navigate all the changes and retrieve previous versions with just a click
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
Clone and restore complete virtual machines within seconds.
Seamlessly migrate virtual machines from one Synology NAS to another.
Create multiple isolated virtual machines for business units or departments.
Conveniently manage your fleet of Synology NAS from a centralized console.
Secure, reliable, and private mail server solution with an intuitive and modern mail client.
Seamless transition between clustered servers in the event of a server failure to minimize the impact on applications.
Shield your Synology NAS from the most sophisticated threats with industry-leading security solutions.
Instantly access your NAS files across multiple devices whenever you want, wherever you are.
Protect your home or business with intelligent monitoring and video management tools.
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
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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
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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
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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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| Hot Swappable Drive | ||
| Notes | "Compatible drive type" indicates drives that have been tested to be compatible with Synology products. This term does not indicate the maximum connection speed of each drive bay. | |
External Ports |
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External Ports
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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
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PCIe Expansion | 1 x Gen3 x8 slot (x8 link) |
File System |
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File System
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Internal Drives |
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| External Drives |
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| Notes | exFAT Access can be installed for free from Package Center in DSM 7.0. In DSM 6.2 or earlier versions, exFAT Access needs to be purchased in Package Center. | |
Appearance |
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Appearance
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Size (Height x Width x Depth) | 166 mm x 282 mm x 243 mm |
| Weight | 5.3 kg | |
Others |
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Others
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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 | 100V to 240V 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
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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
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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
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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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| Maximum Single Volume Size* |
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| 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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| Notes |
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| 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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| Maximum Local User Accounts | 16,000 | |
| Maximum Local Groups | 512 | |
| Maximum Shared Folder | 512 | |
| Maximum Shared Folder Sync Tasks | 32 | |
| Maximum Hybrid Share Folders | 15 | |
| Notes | For more details about the maximum number of Hybrid Share folders, check this article. | |
| Synology High Availability | ||
| Syslog Events per Second | 1,500 | |
Virtualization |
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Virtualization
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VMware vSphere with VAAI | |
| Windows Server 2016 | ||
| Windows Server 2019 | ||
| Citrix Ready | ||
| OpenStack | ||
| Networking Protocols | SMB1 (CIFS), SMB2, SMB3, NFSv3, NFSv4, NFSv4.1, NFS Kerberized sessions, iSCSI, Fibre Channel, 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 | |
| Notes | For an updated list of supported browser versions, check the DSM Technical Specifications. | |
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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| Maximum Users | 4,000 | |
| Maximum Number of Concurrent Users | 400 | |
| Notes | When applicable, systems are tested configured with maximum memory and set to allow the maximum number of connections. | |
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 | |
| Maximum iSCSI Target Number | 256 | |
| Maximum LUN | 512 | |
| LUN Clone/Snapshot, Windows ODX | ||
| Notes | iSCSI Manager has been renamed to SAN Manager in DSM 7.0. | |
| 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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| DLNA Compliance | ||
| Facial Recognition | ||
| Maximum Snapshots per Shared Folder | 1,024 | |
| Maximum of System Snapshots | 65,536 | |
| 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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| Recommended Number of Concurrent Sync Clients | 900 (the number of connections that can be maintained when the recommended number of hosted files was reached) | |
| Recommended Number of Hosted Files | 50,000,000 (applies to files indexed or hosted by Synology Drive. For file access through other standard protocols, refer to the File Services section above) | |
| Notes |
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| Maximum Users | 2,900 | |
| Notes |
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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. | |
| Maximum Connections | 60 | |
