DiskStation DS1821+
High capacity storage and data protection for anyone
Designed for scalability and performance
The 8-bay Synology DS1821+ is aimed at IT enthusiast and SMB customers looking for a powerful and scalable storage solution, its business-grade backup solutions keep users safe and protected from potential data loss, while major improvements to compute capabilities and throughput means workloads are finished faster than ever before.
CPU
AMD Ryzen™
Quad-core 2.2 GHz
Cache Acceleration
Dual M.2 2280 slots for NVMe Cache
Performance
113K 4K random read IOPS1
Scalability
Expand up to 18 drives
with two DX517 expansion units
The performance you need
Reduce transfer times with the DS1821+, designed to accelerate your workloads. Easily add faster networking and NVMe drives to further boost performance.
Up to2,322/1,460 MB/sread/write2
Up to25GbEnetworking3
2 x M.2NVMecache & storage pool4
Storage that fits your needs
Make the most of high-performance networking and file access without taking up unnecessary space. DS1821+ comes equipped with 8 bays and can scale up to 18 bays with 2 DX517 expansion units as your data needs grow.5
8 bays18 bays
144 TB324 TB
DS1821+
Synology iSCSI storage fully supports most virtualization solutions to enhance work efficiency with easy management interface. VMware vSphere 6 and VAAI integration helps offload storage operations and optimizes computation efficiency. Windows Offloaded Data Transfer (ODX) speeds up data transfer and migration rate. OpenStack Cinder support turns your Synology NAS into a block-based storage component.
Ultimate Backup Solution
DS1821+ 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
Powered by Synology DiskStation Manager
Central Management System
Conveniently manage your fleet of Synology NAS from a centralized console.
Synology MailPlus
Secure, reliable, and private mail server solution with an intuitive and modern mail client.
Synology High Availability
Seamless transition between clustered servers in the event of a server failure to minimize the impact on applications.
Security
Shield your Synology NAS from the most sophisticated threats with industry-leading security solutions.
Synology Drive
Instantly access your NAS files across multiple devices whenever you want, wherever you are.
Surveillance
Protect your home or business with intelligent monitoring and video management tools.
Works best with Synology drives
Engineered to handle intensive 24/7 workloads, Synology drives consistently deliver top-grade performance.
DiskStation DS1821+
- 1Status indicator
- 2Alert indicator
- 3Power button and indicator
- 4LAN indicator
- 5Drive status indicator
- 6Drive tray
- 7Drive tray lock
- 8USB 3.2 Gen 1 port
- 9Power port
- 10System fan
- 11PCIe expansion slot
- 12Kensington Security Slot
- 13Expansion port
- 141GbE RJ-45 port
- 15Reset button
- 16USB 3.2 Gen 1 port
Notes:
Performance figures are achieved in the Synology lab with optimized network and configuration settings. Actual performance could vary in different environments. Comparison done against prior-generation 8-bay DS1819+. For full details on the test setup, please visit the Synology performance page here.
Performance figures are obtained through SMB sequential throughput tests using Windows Server 2016 Datacenter on a DS1821+ with a Synology 10GbE NIC and SSD. Actual performance may vary depending on the testing environment, usage, and configuration. See performance charts for more information.
PCIe add-in cards, expansion units, and storage drives are sold separately. Refer to the compatibility list for compatible devices.
Synology SNV3400 series M.2 NVMe SSD drives can be installed through the built-in M.2 slots to enable SSD caching or create SSD storage pools. Drives are sold separately.
Storage figure calculated based on a RAID 5 configuration. Total storage capacity may vary depending on hard drives used and RAID configuration.
Hardware Specifications | ||
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CPU | CPU Model | AMD Ryzen V1500B |
CPU Quantity | 1 | |
CPU Architecture | 64-bit | |
CPU Frequency | 4-core 2.2 GHz | |
Hardware Encryption Engine | ||
Memory | System Memory | 4 GB DDR4 ECC SODIMM |
Memory Module Pre-installed | 4 GB (4 GB x 1) | |
Total Memory Slots | 2 | |
Maximum Memory Capacity | 32 GB (16 GB x 2) | |
Notes |
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Storage | Drive Bays | 8 |
Maximum Drive Bays with Expansion Unit | 18 (DX517 x 2) | |
M.2 Drive Slots | 2 (NVMe) | |
Compatible Drive Type* (See all supported drives) |
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Hot Swappable Drive* | ||
Notes |
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External Ports | RJ-45 1GbE LAN Port | 4 (with Link Aggregation / Failover support) |
USB 3.2 Gen 1 Port* | 4 | |
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 Expansion | 1 x Gen3 x8 slot (x4 link) |
Appearance | Size (Height x Width x Depth) | 166 mm x 343 mm x 243 mm |
Weight | 6 kg | |
Others | System Fan | 120 mm x 120 mm x 2 pcs |
Fan Speed Mode |
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Easy Replacement System Fan | ||
Brightness Adjustable Front LED Indicators | ||
Power Recovery | ||
Noise Level* | 22.2 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 | 59.8 W (Access) 26.18 W (HDD Hibernation) | |
British Thermal Unit | 204.05 BTU/hr (Access) 89.33 BTU/hr (HDD Hibernation) | |
Notes |
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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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Warranty | 3-year hardware warranty, extendable to 5 years with EW201 or Extended Warranty Plus | |
Notes |
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Environment | RoHS Compliant | |
Packaging Content |
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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. |
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.
DSM Specifications | ||
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Maximum Single Volume Size | 108 TB | |
Maximum Internal Volume Number | 64 | |
M.2 SSD Storage Pool Support* | ||
SSD Read/Write Cache (Determining cache size) | ||
SSD TRIM | ||
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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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. | |
File Protocol |
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Maximum Concurrent SMB/AFP/FTP Connections | 1,000 | |
Maximum Concurrent SMB/AFP/FTP Connections (with RAM expansion) | 2,000 | |
Windows Access Control List (ACL) Integration | ||
NFS Kerberos Authentication | ||
Notes |
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Maximum Local User Accounts | 2,048 | |
Maximum Local Groups | 256 | |
Maximum Shared Folder | 512 | |
Maximum Shared Folder Sync Tasks | 16 | |
Maximum Hybrid Share Folders | 10 | |
Folder and Package Backup | ||
Entire System Backup | ||
Notes | Full-system backup requires DSM 7.2 or later. | |
Synology High Availability | ||
Syslog Events per Second | 1,000 | |
Virtualization | VMware ESXi 6.5 and VAAI | |
Windows Server 2016 | ||
Windows Server 2019 | ||
Windows Server 2022 | ||
Citrix Ready | ||
OpenStack | ||
Supported 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 | |
Notes | For an updated list of supported browser versions, check the DSM Technical Specifications. | |
Add-on Packages view the complete package list | ||
Antivirus by McAfee (Trial) | ||
Suggested Maximum Users | 1,500 | |
Suggested Concurrent Users | 150 | |
Notes | When applicable, systems are tested configured with maximum memory and set to allow the maximum number of connections. | |
Download Station | Maximum Concurrent Download Tasks | 80 |
Maximum iSCSI Target Number | 128 | |
Maximum LUN | 256 | |
LUN Clone/Snapshot, Windows ODX | ||
Notes | iSCSI Manager has been renamed to SAN Manager in DSM 7.0. | |
Free Email Accounts | 5 (Additional accounts require purchase of licenses) | |
Suggested Maximum Users | 750 | |
Suggested Concurrent Users | 150 | |
Maximum Server Performance | 1,484,000 emails per day, approx. 45GB | |
Notes |
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DLNA Compliance | ||
Facial Recognition | ||
Object Recognition | ||
Maximum Snapshots per Shared Folder | 1,024 | |
Maximum of System Snapshots | 65,536 | |
Default Licenses | 2 (Additional cameras require purchase of licenses) | |
Suggested Maximum IP Cameras and Total FPS (H.264) |
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Suggested Maximum IP Cameras and Total FPS (H.265) |
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Notes |
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Recommended Number of Concurrent Sync Clients | 550 (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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Suggested Maximum Users | 4,500 | |
Suggested Concurrent Users | 1,800 | |
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 | 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.