Synology Inc.

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

Secure storage for your business

Synology RS2421+/RS2421RP+ are versatile 2U 12-bay storage servers designed to accommodate a diverse set of business environments. Scalable up to 24 drives, they are designed for cost-effective file management and sharing and include powerful backup capabilities designed for businesses with a growing data footprint. The unit delivers 2,200 MB/s 64K sequential read and 1,154 MB/s sequential write performance, and can be optionally enhanced with SSD cache and 10/25Gb Ethernet.

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ComputeAMD Ryzen^™ V1500B quad-core 2.2 GHz

Throughput2,200 MB/s seq. read and 1,154 MB/s seq. write performance

Memory4 GB ECC DDR4, up to 32 GB

ScalabilityUp to 24 drive bays with RX1217(RP)

Built for reliability

Redundant power

Reduce the possibility of power disruptions on a single distribution channel or PDU adversely impacting data and service availability.

Near-zero downtime

Pair two identical devices with Synology High Availability and enable automatic minute-level failover between both devices in the event one server fails. Learn more

Data integrity and protection

ECC memory brings higher system reliability, while the Btrfs file system helps prevent data corruption, supports snapshot technology, and simplifies data protection. Learn more

Customize to suit

Easily adapt the RS2421+/RS2421RP+ to any business environment by adding faster networking, local SSD cache, or storage capacity.

10/25GbE ready

Support for 10/25GbE NICs lets you boost maximum network throughput using Link Aggregation (bonding).

SSD cache

Boost read/write IOPS over HDD-only arrays by up to 16 times or more with NVMe or SATA SSD Cache

Storage expansion

Expand to 24 drive bays with a RX1217(RP) expansion unit

License-free backup solutions

Back up your NAS to other devices

Hyper Backup

Back up files, iSCSI LUNs, installed applications, and system configurations to destinations including Synology C2 Storage, public cloud platforms, USB devices, file servers, local folders, or other Synology NAS. Set and forget backup tasks with regular schedules, enhance security with fine-grained user permissions and encryption, keep backup sizes small with built-in deduplication, and restore data flexibly with multi-versioning. Learn more

Snapshot Replication

Snapshot Replication enables flexible point-in-time snapshots of shared folders and virtual machines with an RPO as low as 5 minutes and recovery within seconds. Learn more

Active Backup Suite

Securely back up Windows clients and servers, Microsoft 365 and Google Workspace accounts, file servers, and VMware and Hyper-V virtual machines with the Active Backup Suite. Leverage built-in deduplication technology to reduce backup sizes and multi-versioning to allow flexible restoration. Learn more

Serving remote workforces

Keep your remote workforce connected with powerful out-of-the-box solutions for collaboration, file sharing, and communication.

Synology Drive

Host your own private cloud behind the safety of your NAS with 100% data ownership and no subscription fees. Learn more

Synology Office

Create documents, spreadsheets, and slides in a multi-user environment. Real-time collaboration and automatic saving make remote work sessions a breeze. Learn more

Synology Chat

Discuss and collaborate with colleagues using secure messaging designed for teams, with mobile, desktop, and browser clients. Learn more

detail_RS2421plus.virtualization_title

DSM streamlines provisioning for and management of virtual machines with full certification for VMware^® vSphere^™, Microsoft^® Hyper-V^®, Citrix^® XenServer^™, and OpenStack virtualization environments.
Synology Storage Console for VMware or Windows platforms lets you manage storage directly from your hypervisor. VMware VAAI integration and Windows ODX help offload storage operations and speed up data transfer. Learn more

Works best with Synology drives

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

HDD

Enterprise Series 3.5" SATA

Plus Series 3.5" SATA

SSD

Enterprise Series 2.5" SATA

Enterprise Series M.2 NVMe

Powered by Synology DiskStation Manager

The web-based DiskStation Manager (DSM) operating system supports a host of native productivity and management solutions.

Central Management System

Conveniently manage your fleet of Synology NAS from a centralized console.

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Synology Drive

Instantly access your NAS files across multiple devices whenever you want, wherever you are.

Learn more

Collaboration Suite

Satisfy all team collaboration needs behind the safety of your own private cloud with Synology Office, Calendar, and Chat.

Learn more

Virtual Machine Manager

Run various operating systems in isolated sandboxes. Seamlessly clone, store, and migrate virtual machines.

Learn more

Security

Secure data with comprehensive built-in security tools to protect your devices against evolving threats.

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Surveillance Station

Complete surveillance solution for recording, monitoring, and management.

Learn more

Hardware Overview

1Power button and indicator
2Status Indicator
3Alert Indicator
4Alert Off Button
5Drive tray

6Drive status indicator
7Rail Kit Release Tab
8Power Port
9PSU Indicators & Alert Off Buttons (RS2421RP+)
10PSU fan

11PSU on/off switch
12Console port
131GbE RJ-45 port
14USB 3.2 Ports
15Expansion port

16Reset button
17PCIe expansion slot

Notes:Network adapter cards, expansion units, other PCIe add-in cards, and storage drives are sold separately. Refer to thecompatibility list for compatible devices.Redundant power only available in the RS2421RP+ model.SSD cache can be enabled by using compatible 2.5" SSDs in drive bays or without occupying drive bays by installing Synology SNV3500 M.2 22110 NVMe SSDs using M2D20 or E10M20-T1 adapter cards, sold separately. The RS2421(RP)+ does not support SNV3400 NVMe SSDs.Users have reported total data size reductions of more than 50% when backing up multiple systems with deduplication technology enabled.

Hardware Specs

Software Specs

Hardware Specifications
CPU
CPU	CPU Model	AMD Ryzen V1500B
	CPU Quantity	1
	CPU Cores	4
	CPU Threads	8
	CPU Architecture	64-bit
	CPU Frequency	2.2 GHz
	Hardware Encryption Engine
Memory
Memory	System Memory	4 GB DDR4 ECC UDIMM
	Total Memory Slots	2
	Maximum Memory Capacity	32 GB (16 GB x 2)
	Notes	Synology may revise pre-installed memory module specifications in response to component lifecycle and supply conditions. All revised components undergo the same rigorous validation to ensure equivalent compatibility, stability, and 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 multi-module memory configurations, all modules must be identical and share the same model number. Check the Product Manual of your Synology product for recommended memory configurations.
Storage
Storage	Drive Bays	12
	Maximum Drive Bays with Expansion Unit	24 (RX1217 x 1)
	Drive Type (See all supported drives)	3.5" SATA HDD 2.5" SATA HDD 2.5" SATA SSD
	Hot Swappable Drive*
	Notes	Synology only guarantees full functionality, reliability, and performance for Synology drives listed on the compatibility list. The use of non-validated components may limit certain functionality and result in data loss and system instability.
External Ports
External Ports	RJ-45 1GbE LAN Port	4
	USB 3.2 Gen 1 Port	2
	Expansion Port	1
	Expansion Port Type	Infiniband
PCIe
PCIe	PCIe Expansion	1 x Gen3 x8 slot (x4 link)
Appearance
Appearance	Form Factor (RU)	2U
	Size (Height x Width x Depth)	88 mm x 482 mm x 552 mm
	Weight	11.5 kg
	Rack Installation Support*	4-post 19" rack (Synology Rail Kit - RKS-02)
	Notes	The rail kit is sold separately
Others
Others	System Fan	60 mm x 60 mm x 3 pcs
	Fan Speed Mode	Full-Speed Mode Cool Mode Quiet Mode
	Easy Replacement System Fan
	Power Recovery
	Noise Level*	50.1 dB(A)
	Scheduled Power On / Off
	Wake on LAN / WAN
	Power Supply Unit / Adapter	500 watts
	AC Input Power Voltage	100V to 240V AC
	Power Frequency	50/60 Hz, Single Phase
	Power Consumption	79.56 watts (Access) 34.89 watts (HDD Hibernation)
	British Thermal Unit	271.65 BTU/hr (Access) 119.13 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 35°C (32°F to 95°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	FCC CE BSMI EAC CCC KC BIS UL 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 Cord X 1 Quick Installation Guide X 1
Optional Accessories
Optional Accessories	DDR4 ECC UDIMM: D4EU01-4G/D4EC-2666-8G/D4EC-2666-16G Expansion Units: RX1217/RX1217RP Enterprise Series 3.5" SATA HDD: HAT5300 Series Plus Series 3.5" SATA HDD: HAT3300 Series Enterprise Series 2.5" SATA SSD: SAT5200 Series M.2 SSD & 10GbE Combo Adapter Card: E10M20-T1 M.2 SSD Adapter Card: M2D20 25GbE Network Interface Card: E25G30-F2 10GbE Network Interface Card: E10G30-F2/E10G30-T2/E10G18-T1 Rail Kit Sliding: RKS-02
	Notes	All memory modules will operate at the maximum frequency specified by the CPU manufacturer.
	Compatibility	Synology Compatibility List

DSM Specifications
Storage Management
Storage Management	Maximum Single Volume Size	108 TB
	Maximum Internal Volume Number	64
	SSD Read/Write Cache (Determining cache size)
	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 RAID 6
	Global Hot Spare Supported RAID Type	Synology Hybrid RAID RAID 1 RAID 5 RAID 6 RAID 10
	Notes	Each internal volume (may consist of multiple drives) is expandable up to 108TB. 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	Btrfs ext4
	External Drives	Btrfs ext4 ext3 FAT32 NTFS HFS+ exFAT
File Services
File Services	File Protocol	SMB AFP NFS FTP WebDAV Rsync
	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	During testing, the maximum number of SSDs supported by this model is installed in a RAID 5 configuration. Regarding data concerning tests with RAM expansion, all memory slots are installed with the maximum capacity of supported RAM. 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	2,048
	Maximum Local Groups	256
	Maximum Shared Folder	512
	Maximum Shared Folder Sync Tasks	16
Hybrid Share
Hybrid Share	Hybrid Share Folder Number	10
Hyper Backup
Hyper Backup	Data & Folder Backup
	Entire System Backup
	Notes	Full-system backup requires DSM 7.2 or later.
High Availability
High Availability	Synology High Availability
Log Center
Log Center	Syslog Events per Second	1,000
Virtualization
Virtualization	VMware vSphere	ESXi 8.0 U2, ESXi 8.0 U1, ESXi 8.0, ESXi 7.0 U3, ESXi 7.0 U2, ESXi 7.0 U1, ESXi 7.0, ESXi 6.7 U3, ESXi 6.7 U2, ESXi 6.7 U1, ESXi 6.7, ESXi 6.5 U3, ESXi 6.5 U2, ESXi 6.5 U1, ESXi 6.5
	Microsoft Hyper-V	Windows Server 2022
	Citrix XenServer	XenServer 8, Citrix Hypervisor 8.2 LTSR CU1
	OpenStack	Cinder
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
Central Management System
Central Management System
Synology Chat
Synology Chat	Maximum Number of Users	150
	Notes	Measured with simulated users, each with an average record of 20,000 messages, emojis, or stickers. The required server response time is below ten seconds. Models with expandable memory are tested with the maximum supported quantity installed.
Download Station
Download Station	Maximum Concurrent Download Tasks	80
SAN Manager
SAN Manager	Maximum iSCSI Target Number	128
	Maximum LUN	256
	LUN Clone/Snapshot, Windows ODX
Synology MailPlus / MailPlus Server
Synology MailPlus / MailPlus Server	Free Email Accounts	5 (Additional accounts require purchase of licenses)
	Suggested Maximum Users	150
	Notes	Models with expandable memory are tested with the maximum supported quantity installed. Learn more about memory requirements. Operating in high-availability mode will incur additional overhead. Features enabled during evaluation: anti-spam, anti-virus, DNSBL, greylist, content scanning, and full-text search (English). Models with more than 4 bays were installed with two SSDs for SSD cache.
Media Server
Media Server	DLNA Compliance
Synology Photos
Synology Photos	Facial Recognition
	Object Recognition
Snapshot Replication
Snapshot Replication	Maximum Snapshots per Shared Folder	512
	Maximum Snapshots per LUN	128
	Maximum Snapshots per System	65,536
	Maximum Replication Tasks for Shared Folders	64
Surveillance Station
Surveillance Station	Default Licenses	2 (Additional cameras require purchase of licenses)
	Maximum IP Cameras and Total FPS (H.264)	1080p: 40 channels, 1050 FPS 3M: 40 channels, 600 FPS 5M: 40 channels, 440 FPS 4K: 32 channels, 320 FPS
	Maximum IP Cameras and Total FPS (H.265)	1080p: 40 channels, 1200 FPS 3M: 40 channels, 1120 FPS 5M: 40 channels, 600 FPS 4K: 40 channels, 480 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 video channels that can be viewed simultaneously is double the maximum number of cameras for the same codec and resolution.
Synology Drive
Synology Drive	Recommended Number of Concurrent Sync Clients	550
	Maximum 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	Models with expandable memory are tested with the maximum supported quantity installed. Exceeding the recommended numbers above will not block application operations, but may result in longer response time. Btrfs file system and non-encrypted shared folders were used during the aforementioned testing.
Synology Office
Synology Office	Maximum Number of Users	1,800
	Notes	Models with expandable memory are tested with the maximum supported quantity installed. Client performance may affect maximum simultaneous editing users. Client PCs used for testing: Intel Core i3-3220 / 8GB RAM
Virtual Machine Manager
Virtual Machine Manager	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
VPN Server	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.