DiskStation® DS1621xs+

On-premises cloud solution built for performance

DS1621xsplus
DS1621xsplus
CPU

CPU

Intel® Xeon D-1527 4-core 2.2 GHz

Memory

Memory

8 GB DDR4 ECC SODIMM, up to 32 GB

High Performance

High Performance

Over 3,100 MB/s sequential read

Scalability

Scalability

Up to 16 drives with DX5171

Supercharge your storage with speedy performance

M.2 SSD support
10GbE support
5-year warranty

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. 

Synology Replacement Service (SRS)

Synology Replacement Service (SRS)

SRS provides free advance replacement units as early as the next business day in selected regions, maximizing the service uptime for your mission-critical storage and ensuring your business continuity.Check service availability here.

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. Learn more

Fast clone

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

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

Synology Drive

Synology Drive

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

Learn more

Active Backup for<br>Microsoft 365 / Google Workspace

Active Backup for
Microsoft 365 / Google Workspace

On-premise backup solution with a centralized dashboard. Optimize storage efficiency with single instancing and block-level deduplication technology.

Google Workspace

office365

Real-time collaboration on your private cloud

Synology Office is a collaboration package combining the convenience and usability of public clouds with the data privacy and security guaranteed by private clouds. It allows you to work seamlessly together on documents and spreadsheets in a protected environment. Learn more

Real-time collaboration on your private cloud

Real-time collaboration on your private cloud
  1. Real-time collaboration on the same online documents to boost productivity,

  2. Instant communication on Synology Chat during the editing of documents or spreadsheets

  3. Version control for you to navigate all the changes and retrieve previous versions with just a click

Virtual Machine Manager

Virtual Machine Manager enables you to test new software in sandboxes, isolate your customers' machines, and increase the flexibility of your server. You can easily run Windows, Linux, and Virtual DSM on your Synology NAS by just a few steps. Learn more

Snapshots for virtual machines

Snapshots for virtual machines

Perfectly clone and restore a virtual machine within seconds.

Live migration

Live migration

Seamlessly migrate Virtual DSM instances from a Synology NAS to another.

Multi-tenant environment

Multi-tenant environment

Create multiple isolated virtual machines for subsidiary business units or departments.

Powered by Synology DiskStation Manager

DiskStation® DS1621xs+

productDS1621xsplusfront view photo
productDS1621xsplusback view photo
  • 1Status indicator
  • 2Alert indicator
  • 3Power button and indicator
  • 4LAN indicator
  • 5Drive status indicator
  • 6Drive tray
  • 7Drive tray lock
  • 8USB 3.0 port
  • 9System fan
  • 10Power port
  • 11Kensington Security Slot
  • 1210GbE RJ-45 port
  • 131GbE RJ-45 port
  • 14Reset button
  • 15Expansion port
  • 16PCIe expansion slot

Notes:

  1. DS1621xs+ can be scaled up to 16 drives with 2 x DX517. Synology expansion units are sold separately.

Hardware Specifications
CPU
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
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
  • Synology reserves the right to replace memory modules with the same or higher frequency based on supplier's product life cycle status. Rest assured that the compatibility and stability have been strictly verified with the same benchmark to ensure identical performance.
  • Please select Synology memory modules for optimum compatibility and reliability. Synology will not provide complete product warranty or technical support if non-Synology memory modules are used for memory expansion.
  • For more information on the recommended memory configurations, visit here.
Storage
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)
  • 3.5" SATA HDD
  • 2.5" SATA HDD
  • 2.5" SATA SSD
  • M.2 2280 NVMe SSD
Hot Swappable Drive*
Notes
  • The hot swappable drive feature is not supported by M.2 SSD slots.
  • "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
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
PCIe
PCIe Expansion 1 x Gen3 x8 slot (x8 link)
File System
File System
Internal Drives
  • Btrfs
  • EXT4
External Drives
  • Btrfs
  • EXT4
  • EXT3
  • FAT
  • NTFS
  • HFS+
  • exFAT
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
Appearance
Size (Height x Width x Depth) 166 mm x 282 mm x 243 mm
Weight 5.3 kg
Others
Others
System Fan 92 mm x 92 mm x 2 pcs
Fan Speed Mode
  • Full-Speed Mode
  • Cool Mode
  • Quiet Mode
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)
British Thermal Unit 214.45 BTU/hr (Access)
116.89 BTU/hr (HDD Hibernation)
Notes
  • Power consumption is measured when it is fully loaded with Western Digital 1TB WD10EFRX hard drive(s).
  • Noise Level Testing Environment: Fully loaded with Seagate 2TB ST2000VN000 hard drive(s) in the idle state. Two G.R.A.S. Type 40AE microphones, each set up 1 meter away from the Synology NAS at the front and rear. Background noise: 16.49-17.51 dB(A); Temperature: 24.25-25.75˚C; Humidity: 58.2-61.8%
Temperature
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
Certification
  • FCC
  • CE
  • BSMI
  • EAC
  • CCC
  • KC
  • VCCI
  • RCM
Warranty
Warranty
5 Years
Notes The warranty period starts from the purchase date as stated on your purchase receipt. (Learn more)
Environment
Environment
RoHS Compliant
Packaging Content
Packaging Content
  • Main Unit X 1
  • Accessory Pack X 1
  • AC Power Cord X 1
  • RJ-45 LAN Cable X 2
  • Quick Installation Guide X 1
Optional Accessories
Optional Accessories
Notes All memory modules will operate at the maximum frequency specified by the CPU manufacturer.
DSM Specifications
Maximum Single Volume Size*
  • 200 TB (32 GB memory required)
  • 108 TB
Maximum Internal Volume Number 256
SSD Read / Write Cache (White Paper)
SSD TRIM
RAID Group
Supported RAID Type
  • RAID F1
  • Basic
  • JBOD
  • RAID 0
  • RAID 1
  • RAID 5
  • RAID 6
  • RAID 10
RAID Migration
  • Basic to RAID 1
  • Basic to RAID 5
  • RAID 1 to RAID 5
  • RAID 5 to RAID 6
Volume Expansion with Larger HDDs
  • RAID F1
  • RAID 1
  • RAID 5
  • RAID 6
  • RAID 10
Volume Expansion by Adding a HDD
  • RAID F1
  • JBOD
  • RAID 5
  • RAID 6
Global Hot Spare Supported RAID Type
  • RAID F1
  • RAID 1
  • RAID 5
  • RAID 6
  • RAID 10
Notes
  • Usable capacity for each volume will be lower than the maximum volume size and is dependent on the filesystem and the amount of system metadata stored.
  • Each internal volume (may consist of multiple drives) is expandable up to 108 TB (with memory less than 32 GB) or 200 TB (with memory equal to or greater than 32 GB).
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
  • Regarding data concerning tests with RAM expansion, all memory slots are installed with the maximum capacity of supported RAM.
  • During testing, the maximum number of SSDs supported by this model is installed in a RAID 5 configuration.
  • The testing standard was based on the maximum number of concurrent connections supported by this model. During the testing, 25% of the connections were used to transfer files concurrently. The transfer process guaranteed that the connections were not interrupted; the minimum transfer speed was not guaranteed.
Maximum Local User Accounts 16,000
Maximum Local Groups 512
Maximum Shared Folder 512
Maximum Shared Folder Sync Tasks 32
Hybrid Share Folder Number 15
Notes For more supported details, please check this article.
Synology High Availability
Syslog Events per Second 1,500
Virtualization
Virtualization
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
  • Google Chrome
  • Firefox
  • Microsoft Edge
  • Safari
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.
Antivirus by McAfee (Trial)
Antivirus by McAfee (Trial)
Maximum Users 4,000
Maximum Number of Concurrent Users 400
Notes When applicable, tested systems are configured with maximum memory and set to allow the maximum number of connections.
Document Viewer
Document Viewer
Download Station
Download Station
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
  • Models with more than 4 bays were installed with two SSDs for SSD cache.
  • For tested models with expandable memory, the maximum amount of RAM was installed.
  • The performance of the mail system will slightly decrease in high-availability mode due to data synchronization between the two servers.
  • Functions that were enabled in all of the tests above: anti-spam, anti-virus, DNSBL, greylist, content scan, full-text search (English only).
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)
Total FPS (H.265) 2250 FPS @ 720p (1280x720)
2250 FPS @ 1080p (1920x1080)
1125 FPS @ 3M (2048x1536)
700 FPS @ 5M (2591x1944)
490 FPS @ 4K (3840x2160)
Notes
  • Maximum IP cameras and FPS figures are tested with the device fully populated with drives and under a continuous recording setup.
  • Actual system capabilities may differ depending on system configuration, drive performance, number of features enabled, and if additional workloads are present.
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
  • Exceeding the recommended numbers above will not block application operations, but may result in longer response time.
  • Utilizing SSD cache can significantly improve performance.
  • For tested models with expandable memory, the maximum amount of RAM was installed.
  • Btrfs file system and non-encrypted shared folders were used during the aforementioned testing.
Maximum Users 2,900
Notes
  • Multiple files were opened for testing and each file was edited by 30 users simultaneously.
  • For tested models with expandable memory, the maximum amount of RAM was installed.
  • Client performance may affect maximum simultaneous editing users. Client PCs used for testing: Intel Core i3-3220 / 8GB RAM
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

Notes:

  1. Model specifications are subject to change without prior notice.
  2. 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.
  3. The actual performance may be lower than lab testing figure due to differences in server configuration, deployment, and the number of active operations.
  4. If usage requirements exceed the specifications above, please contact our regional partners for professional advice.