Synology RackStation RS4021xs+ NAS Rack (3U) Ethernet LAN Black D-1541

SKU
K/RS4021XS+_+16X_HAT5300-16T
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256 TB, 3U, Intel Xeon D-1541 (8x 2.1GHz), 16GB DDR4, 16x 2.5"/3.5", 2x USB 3.2 Gen1, 4x 1GbE RJ-45, 2x 10GbE RJ-45
  • Intel® Xeon® D-1541 8-core 2.1 GHz
  • Built-in dual-port 10GbE
  • 16 GB ECC DDR4 Up to 64 GB
  • Up to 40 drive bays with RX1217(RP)
More Information
Type NAS
Processor Intel Xeon D
Ethernet ports 6
Storage drives installed Yes
SKU K/RS4021XS+_+16X_HAT5300-16T
Manufacturer Synology
Availability In Stock
Product Family RackStation
Securing your business assets
The 16-bay RS4021xs+ provides solid data security and lightening-fast performance with over 234K 4K random read IOPS and 6,258 MB/s sequential read throughput1. Together with its 8-core processor, ECC memory, advanced snapshot technology, and built-in 10GbE connectivity, the RS4021xs+ can support large multi-user environments while handling data-intensive workloads.

Engineered for service continuity
The RS4021xs+ ensures mission-critical data is always available, enabling businesses to deliver the best results, even in the face of disaster.

Redundant power
Dual PSUs provide protection against a PSU failure or accidental cord removal while hot-swappable fans can be replaced without powering down the system.

Maximize service availability
Synology High Availability (SHA) pairs two identical units together creating an active-passive cluster with minute-level failover.

Next-generation file system
Btrfs prevents data corruption and reduces maintenance overheads with advanced storage technologies and optimized snapshots

Customize to your business
The RS4021xs+ includes two PCIe slots for performance, networking, and storage upgrades enabling it to adapt to any business environment2.

Double bandwidth
Upgrade network bandwidth in minutes by 2x or more with Synology’s range of 10GbE NICs.

SSD cache3
Boost read/write IOPS by up to 16 times by enabling SSD cache with our Synology M.2 NVMe adapter cards and SNV3500 SSDs, or by installing one or more 2.5” SAT5200 SSDs.

Storage expansion
Quickly and easily scale up to 40 drives with two RX1217(RP) expansion units.

Hyper Backup
A comprehensive backup and recovery solution for securing data stored on Synology servers. Backup data locally, to another Synology device, rsync server, or cloud-based storage such as Google Drive, Dropbox, S3-compatible destinations, and Synology C2. Deduplication4, integrity checks, and incremental transfer technology reduce bandwidth and storage used.

Snapshot Replication
Easily schedule flexible point-in-time backups of shared folders and iSCSI LUNs with an RPO as low as 5 minutes and recovery in seconds. Set up replication and failover to other Synology storage systems for fast RTOs and minimal service disruption.

Storage for virtualization
Synology iSCSI storage supports mainstream virtualization solutions with an easy management interface to enhance usability. VMware vSphere 6.5 and VAAI integration helps offload storage operations. Windows Offloaded Data Transfer (ODX) speeds up data transfer. OpenStack Cinder support turns your Synology NAS into a block-based storage component. Additionally, Synology Storage Console enables even more simplified storage provisioning and management options in VMware and Windows environments

All-in-one surveillance solution
Synology Surveillance Station transforms the RS4021xs+ into a feature-packed Network Video Recorder solution. Support for up to 90 IP cameras5 and video analytics such as motion detection, no idle zone, foreign object detection, and anomaly detection cater to the most common surveillance scenarios.

Secure and private
AES-256 encryption keeps locally-stored footage secure.

Access from anywhere, anytime
Access recordings and live streams whenever you want using a web browser, desktop client, or the DS cam mobile app.

Real-time alerts
Email, SMS, or push notifications alert you when incidents occur or predefined conditions are met.
Storage
Total installed storage capacity256 TB
Online RAID migrationYes
Online RAID expansionYes
Storage drives installedYes
Installed storage drive typeHDD
Number of storage drives installed16
Supported storage drive typesHDD & SSD
Number of storage drives supported16
Storage drive interfaceSerial ATA III
Storage drive capacity16 TB
Storage drive size3.5"
Hot-swap drive baysYes
RAID supportYes
Supported file systemsBTRFS, FAT32, HFS+, NTFS, exFAT, ext3, ext4
RAID levels0, 1, 5, 6, 10, F1, JBOD
HDD speed7200 RPM
Supported storage drive interfacesSerial ATA II, Serial ATA III
Storage drive sizes supported2.5,3.5"
Processor
Processor manufacturerIntel
Processor threads16
Processor cache12 MB
Processor boost frequency2.7 GHz
CPU configuration (max)1
Conflict-Free processorYes
Processor frequency2.1 GHz
Processor familyIntel® Xeon® D
Processor modelD-1541
Processor cores8
Memory
Internal memory typeDDR4
Internal memory16 GB
Memory clock speed2666 MHz
Maximum RAM supported64 GB
Memory slots4
Memory form factorUDIMM
ECCYes
Network
Link aggregationYes
Ethernet LAN data rate supported (max)10000 Mbit/s
Ethernet LANYes
Ethernet LAN data rates10,100,1000,10000 Mbit/s
Wake-on-LAN readyYes
Supported network protocolsSMB, AFP, NFS, FTP, WebDAV, CalDAV, iSCSI, Telnet, SSH, SNMP, VPN
iSCSI supportYes
Ports & interfaces
USB portYes
USB 3.2 Gen 1 (3.1 Gen 1) Type-A ports quantity2
PCI Express x8 (Gen 3.x) slots2
Ethernet LAN (RJ-45) ports6
Hard drive
RAID supportYes
Supported file systemsBTRFS, FAT32, HFS+, NTFS, exFAT, ext3, ext4
RAID levels0, 1, 5, 6, 10, F1, JBOD
HDD speed7200 RPM
Design
Cooling typeActive
Fan diameter8 cm
Product colourBlack
Number of fans3 fan(s)
LED indicatorsYes
Chassis typeRack (3U)
Technical details
TypeNAS
Device classSmall & Medium Business
Backup functionYes
Backup featuresCloud, iSCSI LUN
Product colourBlack
Number of users16000 user(s)
Noise level44.7 dB
Multilingual supportYes
LED indicatorsYes
Chassis typeRack (3U)
BuzzerYes
Number of fans3 fan(s)
Sustainability complianceYes
Sustainability certificatesUL ECOLOGO
Compliance certificatesCE, RoHS
Performance
Built-in FTP serverYes
System logYes
Share folderCIFS/AFP/NFS/FTP/WebDAV
Browser supportedChrome, Firefox, Edge, Internet Explorer, Safari
TypeNAS
Device classSmall & Medium Business
Backup functionYes
Backup featuresCloud, iSCSI LUN
On/off switchYes
Windows operating systems supportedYes
Mac operating systems supportedYes
Security algorithms256-bit AES, HTTPS, SSH, SSL/TLS
Reset buttonYes
Operating system installedDiskStation Manager
Number of users16000 user(s)
Noise level44.7 dB
Multilingual supportYes
BuzzerYes
Access Control List (ACL)Yes
Third-party supportYes
SnapshotYes
Cooling
Cooling typeActive
Fan diameter8 cm
Number of fans3 fan(s)
Security
Security algorithms256-bit AES, HTTPS, SSH, SSL/TLS
Access Control List (ACL)Yes
Software
Windows operating systems supportedYes
Mac operating systems supportedYes
Operating system installedDiskStation Manager
Management features
On/off switchYes
Reset buttonYes
Power
Power consumption (HDD standby)62.68 W
Power supply locationBuilt-in
Power supply unit (PSU) capacity800 W
AC input voltage100 - 240 V
AC input frequency50 - 60 Hz
Redundant power supply (RPS) supportYes
Power consumption (typical)145.79 W
Weight & dimensions
Width482 mm
Depth656.5 mm
Height132.3 mm
Packaging content
Cables includedAC
Power cables quantity2
Processor special features
Intel VT-x with Extended Page Tables (EPT)Yes
Intel Virtualization Technology for Directed I/O (VT-d)Yes
Intel Virtualization Technology (VT-x)Yes
Intel TSX-NI version1.00
Intel TSX-NIYes
Intel Trusted Execution TechnologyYes
Intel Secure Key Technology version1.00
Intel Enhanced Halt StateYes
Intel 64Yes
Idle StatesYes
Execute Disable BitYes
Enhanced Intel SpeedStep TechnologyYes
Embedded options availableNo
System requirements
Windows operating systems supportedYes
Mac operating systems supportedYes
Operational conditions
Storage temperature (T-T)-20 - 60 °C
Storage relative humidity (H-H)5 - 95%
Operating temperature (T-T)0 - 35 °C
Operating relative humidity (H-H)5 - 95%
Operating altitude0 - 5000 m
Certificates
CertificationFCC, BSMI, VCCI, RCM, EAC, CCC, KC
Packaging data
Cables includedAC

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SKU
K/RS4021XS+_+16X_HAT5300-16T
ES2486DC-2142IT-128G
RS2821RP+/256TB-HAT5300
RS4021XS+/256T/16X16T
RS4021XS+/192T/16X12T
HD6500
Description
Securing your business assets
The 16-bay RS4021xs+ provides solid data security and lightening-fast performance with over 234K 4K random read IOPS and 6,258 MB/s sequential read throughput1. Together with its 8-core processor, ECC memory, advanced snapshot technology, and built-in 10GbE connectivity, the RS4021xs+ can support large multi-user environments while handling data-intensive workloads.

Engineered for service continuity
The RS4021xs+ ensures mission-critical data is always available, enabling businesses to deliver the best results, even in the face of disaster.

Redundant power
Dual PSUs provide protection against a PSU failure or accidental cord removal while hot-swappable fans can be replaced without powering down the system.

Maximize service availability
Synology High Availability (SHA) pairs two identical units together creating an active-passive cluster with minute-level failover.

Next-generation file system
Btrfs prevents data corruption and reduces maintenance overheads with advanced storage technologies and optimized snapshots

Customize to your business
The RS4021xs+ includes two PCIe slots for performance, networking, and storage upgrades enabling it to adapt to any business environment2.

Double bandwidth
Upgrade network bandwidth in minutes by 2x or more with Synology’s range of 10GbE NICs.

SSD cache3
Boost read/write IOPS by up to 16 times by enabling SSD cache with our Synology M.2 NVMe adapter cards and SNV3500 SSDs, or by installing one or more 2.5” SAT5200 SSDs.

Storage expansion
Quickly and easily scale up to 40 drives with two RX1217(RP) expansion units.

Hyper Backup
A comprehensive backup and recovery solution for securing data stored on Synology servers. Backup data locally, to another Synology device, rsync server, or cloud-based storage such as Google Drive, Dropbox, S3-compatible destinations, and Synology C2. Deduplication4, integrity checks, and incremental transfer technology reduce bandwidth and storage used.

Snapshot Replication
Easily schedule flexible point-in-time backups of shared folders and iSCSI LUNs with an RPO as low as 5 minutes and recovery in seconds. Set up replication and failover to other Synology storage systems for fast RTOs and minimal service disruption.

Storage for virtualization
Synology iSCSI storage supports mainstream virtualization solutions with an easy management interface to enhance usability. VMware vSphere 6.5 and VAAI integration helps offload storage operations. Windows Offloaded Data Transfer (ODX) speeds up data transfer. OpenStack Cinder support turns your Synology NAS into a block-based storage component. Additionally, Synology Storage Console enables even more simplified storage provisioning and management options in VMware and Windows environments

All-in-one surveillance solution
Synology Surveillance Station transforms the RS4021xs+ into a feature-packed Network Video Recorder solution. Support for up to 90 IP cameras5 and video analytics such as motion detection, no idle zone, foreign object detection, and anomaly detection cater to the most common surveillance scenarios.

Secure and private
AES-256 encryption keeps locally-stored footage secure.

Access from anywhere, anytime
Access recordings and live streams whenever you want using a web browser, desktop client, or the DS cam mobile app.

Real-time alerts
Email, SMS, or push notifications alert you when incidents occur or predefined conditions are met.
Powerful and cost-efficient Intel® Xeon® D based Enterprise ZFS NAS, optimized for inline deduplication and all-flash applications

The ES2486dc Enterprise ZFS NAS is QNAP’s first high-availability NAS with all-flash arrays and dual active controllers. Powered by an Intel® Xeon® D-2142IT 8 cores/16 threads processor, the ES2486dc supports up to 24 x 2.5-inch SAS 12Gbps SSDs and provides excellent I/O throughputs. Random write performance for all-flash arrays is further driven by the flash-optimized QES 2.1.1 operating system that comes pre-installed on the ES2486dc. The QES uses ZFS to support logical volume management; block-based inline data deduplication and inline compression reduce I/O and SSD storage consumption, which significantly extends SSD lifespan with higher price-performance ratio for all-flash storage arrays.

Active-Active high availability with optimal storage efficiency
In Active-Active storage system architecture, both controllers can provide a comprehensive range of services, which is different from the Active-Standby architecture of single-controller systems. An advantage of Active-Active architecture is the lack of idle computing resources. To leverage the strengths of the ES2486dc Active-Active controller architecture, QNAP recommends creating multiple storage pools and distributing ownership between both controllers to enable simultaneous output from both controllers for improved load balancing.

Active-Standby single-controller system
With two HA systems you are paying twice the price, and the HA system can cause load imbalances because workloads are only processed on the active system. Moreover, a power outage can cause data loss, while network disconnections will invalidate the HA architecture.

Active-Active dual-controller system
Both controllers of the ES2486dc can carry traffic, along with Copy-To-Flash protection against power failure and the dual-path SAS interface design. Besides conserving computing resources, a high-speed, uninterrupted, and high-availability storage service is also provided through communication protocols such as SMB, NFS and iSCSI.

Intel® Xeon® D dual controllers optimize inline deduplication and SSD workloads
Powered by Intel® Xeon® D-2142IT 8 cores/16 threads processors, the ES2486dc delivers massive computing power to maximize inline data deduplication and inline compaction performance. The dual active-active controller architecture provides failover/failback operations since the standby controller can quickly take over if one controller breaks down. Redundant hot-swappable power supplies and cooling fans also provide businesses with near-zero downtime and high availability. The ES2486dc connects to the JBOD enclosure (EJ1600 v2) through dual-path mini-SAS design and can sustain continuous operations even if a JBOD cable is disconnected.

Multi-level cache technology with read and write support boosts storage performance
The ES2486dc simultaneously supports read caches including primary cache (L1 ARC), SSD cache as a secondary cache (L2 ARC), and write cache ZFS Intent Log (ZIL) for synchronous transactions to meet performance demands for various enterprise applications.

Use SAS or SATA SSDs flexibly within your IT budget
Although SATA 6Gbps SSDs provide high-performance affordable storage, this type of drive is unsuitable for dual-controller environments because it lacks dual-port support. By using a QDA-SA3 adapter specially designed for QNAP all-flash Enterprise ZFS NAS, a SATA 6Gbps drive can be used in the 3.5-inch SAS drive bay of the ES2486dc— allowing storage capacity expansions with cost-effective SATA drives. By installing a SATA SSD with the QDA-SA3 into the dual-controller ES2486dc, the SATA SSD can share SAS dual-port advantages to ensure a high-availability and fault-tolerant enterprise storage environment.

PCIe expansion for 25GbE/40GbE high-speed networks
The ES2486dc provides two PCIe Gen 3.0 x8 slots connected to the CPU, allowing you to install lightning-fast 10GbE/25GbE/40GbE network cards to boost virtualization, media streaming, and other bandwidth-demanding applications. Installing a Smart NIC that supports iSER can improve VMware® virtualization performance. You can also install a SAS expansion card ( SAS-12G2E ) for connecting up to seven 16-bay EJ1600 v2 expansion enclosures to seamlessly expand potential storage capacity to over 1PB, with unprecedented performance of up to 48 Gbps per host connection.

Dual controller NAS: High performance, high reliability, and high availability
The ES2486dc adopts dual active-active controllers to provide reliable mission-critical business applications in IT storage.

QES 2.1.1: ZFS-based, and optimized for all flash performance
The ES2486dc features the QES (QNAP Enterprise Storage) 2.1.1 operating system which is based on the simple and efficient FreeBSD kernel and ZFS file system for high-end enterprise applications. QES 2.1.1 not only provides reliable data protection, recovery, and business-class features, it is also optimized for flash storage to drive outstanding performance of all-flash storage arrays, accelerating mission-critical services and eliminate challenges in VDI environments. QES 2.1.1 also comes with Quality of Service (QoS) capabilities to ensure consistent primary storage performance in multi-application environments. The flash-optimized QES 2.1.1 continues the same user experience as the intuitive QTS, thus easy to learn for enterprise users and can be quickly implemented into existing IT infrastructures.

Unleashed SSD potential – cost-effective and agile with ultimate performance
QES 2.1.1 features QNAP’s exclusive Write Coalescing algorithm that further optimizes all-flash performance in ZFS, providing a highly cost-effective all-flash solution for enterprise-class data management and mission-critical services.

Write Coalescing Algorithm
Transforms all random writes to sequential writes along with reduced I/O. Not only does it effectively increase random write performance for all-flash environments, but also improves SSD lifespan.
Software-Defined Over-Provisioning
Users can allocate an additional over-provisioning ratio for SSDs (from 1% to 60%) and Storage Pools (from 1% to 40%) for a constant performance boost over 100%.

Deduplication and compression optimizes storage usage for virtualization
The QES-powered ES2486dc provides businesses with the most cost-effective remote virtual desktop platform and mission-critical information warehousing.

Inline data deduplication
Block-based data deduplication optimizes storage usage and significantly decreases storage capacity requirements.
Inline compression
Shrinks data size to reduce storage I/O workloads for improved performance. In VDI, deduplicated virtual desktops are easily cached to achieve optimal virtual desktop performance.
Inline compaction
Especially helpful for increasing SSD storage utilization efficiency when highly-repetitive data or massive small files (e.g. bank or e-commerce transaction logs) are generated. Delivers higher cost efficiency for all-flash storage systems.

Self-Healing ensures data integrity and reliability
Designed with a focus on data integrity, the QES-based ES2486dc uses its end-to-end checksums to detect and correct silent data corruption caused by hardware defects, firmware bugs or metadata errors. If data integrity violations are detected, QES automatically repairs the data with data from the other mirror before passing it to applications.

Streamlined remote backups with nearly limitless snapshots and SnapSync
The ES2486dc supports up to 65,535 snapshots for iSCSI LUN and shared folders. In other words, if one snapshot is created every hour, and 24 snapshots are created per day, you can create up to 7 years’ worth of snapshots without having to delete any! The ES2486dc also replicates snapshots to remote servers through block-level SnapSync. In the event of a primary site failure, SnapSync assists businesses to resume essential services in the shortest possible time.

VMware SRM
SnapSync supports VMware Site Recovery Manager (SRM), which offers enterprise-class remote backup and disaster recovery solutions for virtual applications. With the Storage Replication Adapter (SRA) for SRM, operation overheads of the ESXi® server can be offloaded to a QNAP NAS to accelerate and simplify virtual machine backup and restoration.

Business Continuity
Copy-on-write technology enables instant QES snapshot creation without affecting ongoing data writing. SnapSync supports incremental backups, real-time deduplication, and compression. The source ES2486dc will perform deduplication before compressing the metadata to reduce synchronized data and save bandwidth resources.

Create VMware/Windows backups for VSS-Aware applications using QNAP Snapshot Agent
QNAP NetBak Replicator is easy-to-use with VSS-aware backup software, helping businesses to create complete backups in data centers and virtualization environments without requiring additional software. To build a QNAP Snap Agent and VSS Hardware Provider operating environment, all applications (including VSS Service, Requestor, Provider and QNAP Snap Agent) can be deployed with VSS-Aware applications on the same server, and the minimal requirements are only one ES2486dc and one server for it to be operational.

Compatible with VMware, Microsoft, and Citrix virtualization, and supports iSER
The ES2486dc supports VMware® vSphere® 6.5, Windows Server® 2019, and Citrix XenServer® 7.0 for flexible deployment and management in virtualization environments. It also supports VMware® VAAI and Microsoft® ODX to increase performance by offloading server loading for ESXi® server and Hyper-V® respectively. The QNAP vSphere Client plug-in and Web plug-in are also supported to increase operations and management efficiency in virtualization applications. The ES2486dc and VMware® ESXi server installed with Smart NICs that support iSER can acquire iSER advantages to offload CPU workloads with boosted VMware® virtualization performance.

OpenStack Ready for exploring out-of-the-box enterprise cWarraloud services
QES supports OpenStack® Cinder and Manila file-sharing services. With the QNAP Cinder Driver, the ES2486dc can provide block-level storage space for virtual machines. It not only accelerates the deployment of virtual machines and enhances virtual machine image access efficiency through iSCSI, but it is also easier to integrate into commercial cloud storage platforms, providing businesses with a flexible, easy-to-use, and low-cost storage solution.
Versatile and scalable storage
Synology RS2821RP+ is a 3U 16-bay storage server designed to accommodate a diverse set of business requirements. Scalable to 28 drives, the unit provides powerful backup and restoration functionality for the SMB sector. It delivers 2,200 MB/s sequential read and 105K 4K random read performance, and can be upgraded with SSD cache and 10/25Gb Ethernet options.

High performance storage for anything
Over 105K/59K random read/write IOPS and up to 2,220/1,164 MB/s sequential read/write throughput ensure ample performance for demanding workloads.

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.

Data integrity and protection
ECC memory prevents data corruption, while the Btrfs file system brings higher reliability, snapshot technology, and simplified data protection.

Customize to suit
Easily adapt the RS2821RP+ 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 server throughput up to five times 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
On-demand drive bays
Expand to 28 drive bays with one RX1217(RP) expansion unit

License-free backup solutions
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.

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.

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.

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.

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

Synology Chat
Chat and collaborate with colleagues using secure end-to-end encryption on with mobile, desktop, and browser clients.

Storage for virtualization
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.

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

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.
Synology Drive
Instantly access your NAS files across multiple devices whenever you want, wherever you are.
Collaboration Suite
Satisfy all team collaboration needs behind the safety of your own private cloud with Synology Office, Calendar, and Chat.
Virtual Machine Manager
Run various operating systems in isolated sandboxes. Seamlessly clone, store, and migrate virtual machines.
Security
Shield your Synology NAS from the most sophisticated threats with industry-leading security solutions.
Surveillance
Protect your home or business with intelligent monitoring and video management tools.
Securing your business assets
The 16-bay RS4021xs+ provides solid data security and lightening-fast performance with over 234K 4K random read IOPS and 6,258 MB/s sequential read throughput1. Together with its 8-core processor, ECC memory, advanced snapshot technology, and built-in 10GbE connectivity, the RS4021xs+ can support large multi-user environments while handling data-intensive workloads.

Engineered for service continuity
The RS4021xs+ ensures mission-critical data is always available, enabling businesses to deliver the best results, even in the face of disaster.

Redundant power
Dual PSUs provide protection against a PSU failure or accidental cord removal while hot-swappable fans can be replaced without powering down the system.

Maximize service availability
Synology High Availability (SHA) pairs two identical units together creating an active-passive cluster with minute-level failover.

Next-generation file system
Btrfs prevents data corruption and reduces maintenance overheads with advanced storage technologies and optimized snapshots

Customize to your business
The RS4021xs+ includes two PCIe slots for performance, networking, and storage upgrades enabling it to adapt to any business environment2.

Double bandwidth
Upgrade network bandwidth in minutes by 2x or more with Synology’s range of 10GbE NICs.

SSD cache3
Boost read/write IOPS by up to 16 times by enabling SSD cache with our Synology M.2 NVMe adapter cards and SNV3500 SSDs, or by installing one or more 2.5” SAT5200 SSDs.

Storage expansion
Quickly and easily scale up to 40 drives with two RX1217(RP) expansion units.

Hyper Backup
A comprehensive backup and recovery solution for securing data stored on Synology servers. Backup data locally, to another Synology device, rsync server, or cloud-based storage such as Google Drive, Dropbox, S3-compatible destinations, and Synology C2. Deduplication4, integrity checks, and incremental transfer technology reduce bandwidth and storage used.

Snapshot Replication
Easily schedule flexible point-in-time backups of shared folders and iSCSI LUNs with an RPO as low as 5 minutes and recovery in seconds. Set up replication and failover to other Synology storage systems for fast RTOs and minimal service disruption.

Storage for virtualization
Synology iSCSI storage supports mainstream virtualization solutions with an easy management interface to enhance usability. VMware vSphere 6.5 and VAAI integration helps offload storage operations. Windows Offloaded Data Transfer (ODX) speeds up data transfer. OpenStack Cinder support turns your Synology NAS into a block-based storage component. Additionally, Synology Storage Console enables even more simplified storage provisioning and management options in VMware and Windows environments

All-in-one surveillance solution
Synology Surveillance Station transforms the RS4021xs+ into a feature-packed Network Video Recorder solution. Support for up to 90 IP cameras5 and video analytics such as motion detection, no idle zone, foreign object detection, and anomaly detection cater to the most common surveillance scenarios.

Secure and private
AES-256 encryption keeps locally-stored footage secure.

Access from anywhere, anytime
Access recordings and live streams whenever you want using a web browser, desktop client, or the DS cam mobile app.

Real-time alerts
Email, SMS, or push notifications alert you when incidents occur or predefined conditions are met.
Securing your business assets
The 16-bay RS4021xs+ provides solid data security and lightening-fast performance with over 234K 4K random read IOPS and 6,258 MB/s sequential read throughput1. Together with its 8-core processor, ECC memory, advanced snapshot technology, and built-in 10GbE connectivity, the RS4021xs+ can support large multi-user environments while handling data-intensive workloads.

Engineered for service continuity
The RS4021xs+ ensures mission-critical data is always available, enabling businesses to deliver the best results, even in the face of disaster.

Redundant power
Dual PSUs provide protection against a PSU failure or accidental cord removal while hot-swappable fans can be replaced without powering down the system.

Maximize service availability
Synology High Availability (SHA) pairs two identical units together creating an active-passive cluster with minute-level failover.

Next-generation file system
Btrfs prevents data corruption and reduces maintenance overheads with advanced storage technologies and optimized snapshots

Customize to your business
The RS4021xs+ includes two PCIe slots for performance, networking, and storage upgrades enabling it to adapt to any business environment2.

Double bandwidth
Upgrade network bandwidth in minutes by 2x or more with Synology’s range of 10GbE NICs.

SSD cache3
Boost read/write IOPS by up to 16 times by enabling SSD cache with our Synology M.2 NVMe adapter cards and SNV3500 SSDs, or by installing one or more 2.5” SAT5200 SSDs.

Storage expansion
Quickly and easily scale up to 40 drives with two RX1217(RP) expansion units.

Hyper Backup
A comprehensive backup and recovery solution for securing data stored on Synology servers. Backup data locally, to another Synology device, rsync server, or cloud-based storage such as Google Drive, Dropbox, S3-compatible destinations, and Synology C2. Deduplication4, integrity checks, and incremental transfer technology reduce bandwidth and storage used.

Snapshot Replication
Easily schedule flexible point-in-time backups of shared folders and iSCSI LUNs with an RPO as low as 5 minutes and recovery in seconds. Set up replication and failover to other Synology storage systems for fast RTOs and minimal service disruption.

Storage for virtualization
Synology iSCSI storage supports mainstream virtualization solutions with an easy management interface to enhance usability. VMware vSphere 6.5 and VAAI integration helps offload storage operations. Windows Offloaded Data Transfer (ODX) speeds up data transfer. OpenStack Cinder support turns your Synology NAS into a block-based storage component. Additionally, Synology Storage Console enables even more simplified storage provisioning and management options in VMware and Windows environments

All-in-one surveillance solution
Synology Surveillance Station transforms the RS4021xs+ into a feature-packed Network Video Recorder solution. Support for up to 90 IP cameras5 and video analytics such as motion detection, no idle zone, foreign object detection, and anomaly detection cater to the most common surveillance scenarios.

Secure and private
AES-256 encryption keeps locally-stored footage secure.

Access from anywhere, anytime
Access recordings and live streams whenever you want using a web browser, desktop client, or the DS cam mobile app.

Real-time alerts
Email, SMS, or push notifications alert you when incidents occur or predefined conditions are met.
All the space you will ever need
With 60 bays in a 4U rackmount enclosure and support for up to 300 drives after expansion, the Synology HD6500 is the ideal high-density storage solution for large-scale warm and cold storage applications such as full system backups, video post-production, and large surveillance deployments.

Consistent performance at five times the size
The HD6500 is designed to scale up to 5 times in capacity with four additional RX6022sas expansion units. SAS multipath-enabled connectivity provides up to double the typical performance together and increased redundancy.

Built for high reliability
The HD6500 is built to keep mission-critical data and services accessible, so that businesses can continue to perform even when disaster strikes.

Out-of-band (OOB) management
Simplify troubleshooting by managing powered-down devices remotely and accessing critical logs through a dedicated interface.

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

High-reliability expansion architecture
Redundant SAS links prevent single points of failure from affecting other expansion units, ensuring higher data and service availability.

Powerful networking options
The HD6500 supports a large variety of networking interfaces, protocols, and configurations, whether you need fast sequential transfer, support for simultaneous connections, or high network redundancy.

Built-in fast connectivity
Three Gigabit Ethernet and two 10GbE RJ-45 ports allow for rapid transfer speeds right out of the box.

Mix and match network ports
Add extra 10GbE SFP+/RJ-45, 25GbE SFP28, or Fibre Channel ports in varying configurations by leveraging the four expansion slots.2

Failover and network balancing
Bond multiple network interfaces with Link Aggregation to enable automatic network failover and load balancing.

Consolidate your data storage
Back up your backup solutions, bring all your files together in one place, or bring distributed surveillance deployments under central control.

Massive file server
Host and retrieve massive files from extensive archives whenever needed. Provide user friendly access and set up powerful cross-site syncing.

Central backup server
Protect large numbers of PCs, servers, Synology systems, and hypervisors, or back up your backup servers with a central storage solution.

Main surveillance storage
Manage distributed deployments of hundreds of local recording servers and thousands of IP cameras centrally.

Get more with DiskStation Manager
Take advantage of a host of native productivity, management, and security solutions available in the web-based Synology DSM operating system.
Short Description
256 TB, 3U, Intel Xeon D-1541 (8x 2.1GHz), 16GB DDR4, 16x 2.5"/3.5", 2x USB 3.2 Gen1, 4x 1GbE RJ-45, 2x 10GbE RJ-45
24x 2.5", Intel Xeon D-2142IT, 64 GB RDIMM DDR4 ECC, 4 GB Flash, SFP+, LAN, 700W, 90-264V, 88.3 x 483 x 545.1 mm, 27.41 kg
256TB, 3U, AMD Ryzen V1500B (4x 2.2GHz), 4GB DDR4, 16x 2.5"/3.5" SATA, 4x RJ-45, 2x USB 3.2 Gen1
256 TB, 3U, Intel Xeon D-1541 (8x 2.1GHz), 16GB DDR4, 16x 2.5"/3.5", 2x USB 3.2 Gen1, 4x 1GbE RJ-45, 2x 10GbE RJ-45
192 TB, 3U, Intel Xeon D-1541 (8x 2.1GHz), 16GB DDR4, 16x 2.5"/3.5", 2x USB 3.2 Gen1, 4x 1GbE RJ-45, 2x 10GbE RJ-45
High Density HD6500, 2 x Intel Xeon Silver 4210R 10-core, 64 GB DDR4 ECC RDIMM, 60 x 3.5" SAS HDD, Rackmount 4U
Manufacturer
Synology
QNAP
Synology
Synology
Synology
Synology