Refurbished DiskStation DS420j

An essential entry-level NAS for your home

Synology Certified Refurbished

Access Synology solutions in a cost-effective and environmentally responsible way. All certified refurbished products are put through extensive testing, comply with stringent quality standards, and come with a 2-year warranty.

More about Synology Certified Refurbished

Build a private cloud for your home

Download Datasheet

Secure cloud storage

Flexibly store up to 64 TB of data with 100% ownership and enjoy multi-platform access from anywhere.

Data sharing made easy

Safely share files and media over your private cloud for easier collaboration and better productivity.

Versatile video surveillance

Leverage intuitive surveillance tools to protect your premises and store footage from up to 16 IP cameras.

Create a private cloud hub for your data

Import and sync data scattered across PCs, Macs, phones, and external storage devices to implement well-organized file management for your business. Learn more

Multi-device access

Browse, access, edit, and share files securely and conveniently via desktop, mobile, or web browser platforms. Use intuitive admin tools to track and set file permissions and control access to documents, files, and other data.

On-demand sync

Save space on your personal devices by only synchronizing the files you need from your Synology system. Pin frequently accessed files for convenient offline accessibility.

Cloud integration

Sync your private storage servers with public cloud services such as Google Drive, Dropbox, and Microsoft OneDrive. Retain local copies of your cloud data for centralized management and data ownership. Learn more

Versatile storage solution for essential needs

Manage and organize photos efficiently, back up and secure your digital data, and safeguard your physical premises with the DS420j.

Smart and secure photo management

Store and organize photos, albums, and other media with smart and intuitive features. Back up your memories with the mobile app, and leverage privacy-focused options to share media securely with friends, family, or colleagues. Learn more

Protect all your data

Safeguard your digital world and back up all your documents, files, photos, and more with license-free backup solutions.

Automatically back up memories and files

Safeguard mobile media such as photos and videos by automatically storing remote copies onto Synology Photos or Synology Drive.

Survive cyberattacks and prevent data leaks

Protect your data against ransomware attacks or accidental deletion with real-time or scheduled backups of computer folders with Synology Drive.

Intuitive video surveillance

Secure your home or business with a powerful solution to monitor, archive, and analyze footage centrally. Learn more

Wide device compatibility

Connect up to 16 IP cameras by selecting from a wide variety of over 8,300 validated models or ONVIF devices.

Access from anywhere

Monitor video streams in real time via web browsers, desktop clients, or mobile apps to protect your premises 24/7. Set up alerts and triggers to get notified of suspicious activity.

Multi-layered backup solutions

Leverage Synology solutions to back up all data stored on your DS420j onto a secondary server, external storage device, or the cloud.

Back up your Synology device, including system settings, applications, and shared folders, save space with data deduplication, and store copies to multiple destinations. Learn more

Works best with Synology drives

Engineered to handle intensive 24/7 workloads, Synology drives consistently deliver top-grade performance.

HDD

Plus Series 3.5" SATA

Hardware Overview

1Status indicator
2LAN indicator
3Power button and indicator

4Drive status indicator
51GbE RJ-45 port
6Power port

7Kensington Security Slot
8System fan
9USB 3.0 port

10Reset button

More ways to harness your NAS

File management

Store, access, and share files safely and efficiently, thanks to built-in solutions available in Synology DSM.

Learn more

Home surveillance

Monitor camera footage from anywhere, set up event alerts, and use other intuitive tools to secure your premises.

Learn more

Ransomware prevention

Reduce the threat posed by cyberattacks by leveraging Synology solutions to protect your devices.

Learn more

Notes:Raw capacity. Usable storage capacity may vary depending on drives used and RAID configuration.Supports up to 16 IP cameras on a single Synology server with Synology Surveillance Station. Up to 10,000 cameras can be managed per deployment by adding more recording servers with Surveillance Station CMS. Surveillance Station includes 2 free licenses. Connecting more cameras and devices requires additional licenses. Learn more

Hardware Specifications
CPU
CPU	CPU Model	Realtek RTD1296
	CPU Quantity	1
	CPU Core	4
	CPU Architecture	64-bit
	CPU Frequency	1.4 GHz
	Hardware Encryption Engine
Memory
Memory	System Memory	1 GB DDR4 non-ECC
	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.
Storage
Storage	Drive Bays	4
	Drive Type (See all supported drives)	3.5" SATA HDD 2.5" SATA HDD 2.5" SATA SSD
	Hot Swappable Drive*
External Ports
External Ports	RJ-45 1GbE LAN Port	1
	USB 3.2 Gen 1 Port	2
Appearance
Appearance	Size (Height x Width x Depth)	184 mm x 168 mm x 230 mm
	Weight	2.21 kg
Others
Others	System Fan	80 mm x 80 mm x 2 pcs
	Fan Speed Mode	Full-Speed Mode Cool Mode Quiet Mode Low-power Mode
	Brightness Adjustable Front LED Indicators
	Power Recovery
	Noise Level*	20.6 dB(A)
	Scheduled Power On / Off
	Wake on LAN / WAN
	Power Supply Unit / Adapter	90 watts
	AC Input Power Voltage	100V to 240V AC
	Power Frequency	50/60 Hz, Single Phase
	Power Consumption*	21.71 watts (Access) 7.88 watts (HDD Hibernation)
	British Thermal Unit	74.03 BTU/hr (Access) 26.87 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)
	Operating Humidity	8% to 80% RH
	Storage Humidity	5% to 95% RH
Certification
Certification	EAC CCC BIS FCC CE BSMI VCCI RCM
Warranty
Warranty	2 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 Adapter X 1 AC Power Cord X 1 RJ-45 LAN Cable X 1 Quick Installation Guide X 1
Optional Accessories
Optional Accessories	Plus Series 3.5" SATA HDD: HAT3300 Series

DSM Specifications
Storage Management
Storage Management	Maximum Single Volume Size	108 TB
	Maximum Internal Volume Number	64
	SSD TRIM
	Supported RAID Type	Synology Hybrid RAID 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	Synology Hybrid RAID RAID 1 RAID 5 RAID 6 RAID 10
	Volume Expansion by Adding a HDD	Synology Hybrid RAID JBOD RAID 5
	Global Hot Spare Supported RAID Type	Synology Hybrid RAID RAID 1 RAID 5
	Notes	Actual maximum storage pool and volume sizes depend on drive sizes used, the number of drive bays available, and the RAID configuration. 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.
File System
File System	Internal Drives	ext4
	External Drives	ext4 ext3 FAT32 NTFS HFS+ exFAT
File Services
File Services	File Protocol	SMB AFP NFS FTP WebDAV Rsync
	Maximum Concurrent SMB/AFP/FTP Connections	100
	Windows Access Control List (ACL) Integration
	NFS Kerberos Authentication
	Notes	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.
Account & Shared Folder
Account & Shared Folder	Maximum Local User Accounts	1,024
	Maximum Local Groups	256
	Maximum Shared Folder	256
	Maximum Shared Folder Sync Tasks	4
Hyper Backup
Hyper Backup	Folder and Package Backup
Log Center
Log Center
	Syslog Events per Second	200
General Specifications
General Specifications	Supported Protocols	SMB1 (CIFS), SMB2, SMB3, NFSv3, NFSv4, NFSv4.1, NFS Kerberized sessions, iSCSI, HTTP, HTTPs, FTP, SNMP, LDAP, CalDAV
	Supported Browsers	Chrome Firefox 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.
Add-on Packages view the complete package list
Synology Chat
Synology Chat
Download Station
Download Station
	Maximum Concurrent Download Tasks	80
SAN Manager
SAN Manager
	Maximum iSCSI Target Number	10
	Maximum LUN	10
Media Server
Media Server
	DLNA Compliance
Synology Photos
Synology Photos
	Facial Recognition
Surveillance Station
Surveillance Station
	Default Licenses	2 (Additional cameras require purchase of licenses)
	Suggested Maximum IP Cameras and Total FPS (H.264)	1080p: 16 channels, 288 FPS 3M: 15 channels, 150 FPS 5M: 10 channels, 100 FPS 4K: 7 channels, 70 FPS
	Suggested Maximum IP Cameras and Total FPS (H.265)	1080p: 16 channels, 384 FPS 3M: 16 channels, 256 FPS 5M: 16 channels, 160 FPS 4K: 10 channels, 100 FPS
	Notes	Performance figures are obtained from testing conducted with the device fully populated with drives, with their default memory configuration, and under a continuous recording setup. Actual system capabilities may vary based on configuration, drive performance, enabled features, and the presence of additional workloads. Use NVR Selector to quickly find a suitable model based on your requirements. The number of streams that can be viewed simultaneously is twice the suggested maximum number of cameras. For example, if the suggested maximum number of cameras for a model is 10 under H.264, 1080p, the model can support up to 20 streams of the same specification at the same time.
Synology Drive
Synology Drive
	Recommended Number of Concurrent Sync Clients	200
	Maximum Number of Hosted Files	500,000 (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. EXT4 file system and non-encrypted shared folders were used during the aforementioned testing.
Synology Office
Synology Office
	Maximum Number of Users	200
	Notes	Client performance may affect maximum simultaneous editing users. Client PCs used for testing: Intel Core i3-3220 / 8GB RAM
VPN Server
VPN Server
	Maximum Connections	10

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.