QNAP ES1686DC-R2-2123IT-64G 16-Bay Dual Controller Enterprise ZFS NAS, 2.5/3.5 in. SAS 12G/6G, Xeon D-2123IT 1.9GHz CPU, 64GB RAM

QNAP ES1686dc-R2-2123IT-64G 16-Bay Dual-Controller Enterprise ZFS NAS

The QNAP ES1686dc-R2-2123IT-64G is a high-availability 16-bay dual-controller Enterprise ZFS NAS designed for mission-critical business storage, virtualisation, databases and enterprise applications. Featuring two active-active controller modules, each powered by an Intel Xeon D-2123IT 4-core processor with 32GB DDR4 ECC memory, the ES1686dc R2 combines 16 hot-swappable 12Gb/s SAS drive bays, extensive 10GbE SFP+ connectivity, redundant power and QNAP's ZFS-based QES operating system. Advanced data protection features including snapshots, SnapSync, inline deduplication and compression make it a powerful platform for organisations requiring resilient, highly available enterprise storage.

Dual Active-Active Controllers for High Availability

The QNAP ES1686dc R2 is built around a dual active-active controller architecture, helping eliminate the storage controller as a single point of failure.

Each controller module includes its own:

• Intel Xeon D processor
• ECC system memory
• Network connectivity
• PCIe expansion
• Cache-to-Flash protection
• Management connectivity

If one controller becomes unavailable, the high-availability architecture is designed to maintain access to storage services through the remaining controller.

Combined with redundant power supplies and dual-path SAS architecture, the ES1686dc R2 provides the resilience required for business-critical enterprise storage.

Dual Intel Xeon D-2123IT 4-Core Processors

Each controller is powered by an Intel Xeon D-2123IT 4-core processor operating at 2.20GHz with burst speeds up to 3.0GHz.

The dual-controller system therefore contains two independent enterprise-class Intel Xeon D processors dedicated to storage operations.

Intel AES-NI hardware-accelerated encryption is supported, helping provide secure storage while reducing the processing overhead associated with encryption.

The Xeon D architecture is well suited to applications including:

• Enterprise virtualisation
• Business databases
• File services
• Virtual Desktop Infrastructure
• Private cloud infrastructure
• Backup and disaster recovery
• Shared enterprise storage

64GB DDR4 ECC Memory

The ES1686dc-R2-2123IT-64G includes 64GB of DDR4 ECC memory, with 32GB installed in each controller.

Each controller is supplied with:

• 32GB RDIMM DDR4 ECC
• 4 × 8GB memory modules
• 8 RDIMM/LRDIMM memory slots
• Maximum capacity of 512GB

Across the complete dual-controller system, memory can therefore be expanded to a maximum of 1TB.

ECC memory provides additional protection against memory errors, making it particularly appropriate for enterprise storage systems handling critical business data.

16 Hot-Swappable 12Gb/s SAS Drive Bays

The ES1686dc R2 provides 16 hot-swappable 3.5-inch drive bays with 12Gb/s SAS connectivity, backward compatible with 6Gb/s SAS.

Supported drive types include:

• 3.5-inch SAS hard disk drives
• 2.5-inch SAS hard disk drives
• 2.5-inch SAS solid-state drives

This allows the ES1686dc-R2 to be configured for high-capacity storage using enterprise SAS HDDs, high-performance storage using SAS SSDs, or a combination appropriate to the required workload.

Enterprise 12Gb/s SAS Storage Architecture

The ES1686dc R2's 12Gb/s SAS architecture provides the performance, reliability and dual-path connectivity required for demanding enterprise storage.

Dual-path SAS connectivity complements the dual-controller design, helping maintain access to installed drives if an individual controller or storage path becomes unavailable.

This architecture makes the ES1686dc R2 particularly well suited to applications where maintaining continuous access to business data is a priority.

SAS HDD and SSD Flexibility

Support for both 3.5-inch and 2.5-inch SAS drives gives organisations considerable flexibility when configuring the ES1686dc-R2.

Enterprise SAS HDDs can provide high-capacity storage for:

• File services
• Backup repositories
• Data archives
• Virtual machine storage
• Shared business data

For more performance-intensive applications, 2.5-inch SAS SSDs can deliver substantially higher IOPS and lower latency for:

• Databases
• Virtual machines
• VDI
• Transactional workloads
• High-I/O enterprise applications

Eight Integrated 10GbE SFP+ Ports

The ES1686dc-R2 provides extensive high-speed networking, with four 10 Gigabit Ethernet SFP+ interfaces per controller.

Across the complete dual-controller system, this provides eight integrated 10GbE SFP+ ports.

10GbE connectivity provides substantial bandwidth for applications including:

• Virtualisation
• iSCSI storage
• High-performance file sharing
• Database workloads
• Backup
• Remote replication
• Large file transfers
• Data centre storage networks

The multiple interfaces also provide flexibility when designing redundant storage networks and separating different types of storage traffic.

Additional Ethernet Connectivity

Each controller also provides three Ethernet RJ45 interfaces, with one assigned for remote management.

These interfaces provide additional flexibility for management and network connectivity alongside the system's eight 10GbE SFP+ ports.

The combination of multiple Ethernet interfaces across both controllers allows storage and management traffic to be appropriately separated according to the network design.

PCIe Gen3 Expansion

Each controller provides two PCIe Gen3 x8 expansion slots, giving the complete ES1686dc-R2 four PCIe expansion slots.

Compatible expansion options can include:

• Higher-speed network adapters
• 25GbE network connectivity
• SAS expansion cards

PCIe expansion allows the ES1686dc R2 to adapt to changing network and storage requirements over its operational life.

Enterprise Cache Architecture

The ES1686dc R2 incorporates an enterprise caching architecture designed to improve performance while protecting critical write data.

Caching technologies include:

• L1 ARC Read Cache: System RAM
• L2 ARC Read Cache: SSD
• ZIL Write Cache: NVRAM with Cache-to-Flash protection

This architecture helps accelerate demanding enterprise workloads while maintaining the data protection expected from a high-availability storage platform.

Cache-to-Flash Data Protection

Each controller includes a dedicated 64GB M.2 SSD for Cache-to-Flash (C2F) protection.

Cache-to-Flash technology helps protect cached write data during unexpected power interruptions.

This is particularly important in enterprise storage environments where uncommitted write data must be protected against sudden power or controller failures.

QES Enterprise ZFS Operating System

The ES1686dc R2 runs QNAP QES, an enterprise storage operating system based on ZFS.

ZFS provides advanced data integrity, storage efficiency and snapshot technologies designed for demanding enterprise environments.

QES capabilities include:

• ZFS-based storage
• Snapshots
• SnapSync
• Inline block-level data deduplication
• Inline data compression
• SMB file services
• NFS
• iSCSI

This allows the ES1686dc R2 to support both enterprise file storage and block-level storage applications.

Inline Block-Level Data Deduplication

QES supports inline block-level data deduplication, helping reduce physical storage consumption when workloads contain duplicate data.

Deduplication can be particularly effective for:

• Virtual Desktop Infrastructure
• Virtual machine environments
• Repeated operating system images
• Development and testing environments
• Enterprise backup datasets

By eliminating duplicate data blocks, organisations can potentially store substantially more logical data within the available physical storage capacity.

Inline Data Compression

Inline compression provides an additional method of improving storage efficiency.

Compressible data can be stored using less physical capacity, helping organisations make more efficient use of their enterprise SAS storage.

When combined with block-level deduplication, compression can significantly improve effective storage utilisation for suitable workloads.

ZFS Snapshots for Data Protection

QES supports extensive ZFS snapshot technology, allowing efficient point-in-time copies of stored data to be created.

Snapshots can help protect against:

• Accidental deletion
• Unwanted file changes
• Data corruption
• Application errors
• Ransomware-related data modification

Point-in-time recovery can allow administrators to restore affected files or storage volumes quickly without requiring a complete recovery from conventional backup media.

SnapSync Remote Replication

QNAP SnapSync provides snapshot-based remote replication between compatible Enterprise ZFS systems.

SnapSync can form part of an organisation's disaster recovery and business continuity strategy by maintaining replicated data on another compatible system.

Combined with dual active-active controllers, snapshots, redundant networking and redundant power, SnapSync provides another layer of protection for critical enterprise data.

Enterprise Virtualisation Storage

The ES1686dc-R2-2123IT-64G provides a strong platform for shared enterprise virtualisation storage.

Its combination of:

• Dual active-active controllers
• Dual Intel Xeon D processors
• 64GB ECC memory
• 12Gb/s SAS storage
• Eight 10GbE SFP+ interfaces
• ZFS data protection
• Inline deduplication and compression

makes it suitable for hosting virtual machine datastores and other shared virtualisation workloads.

Deduplication can be particularly valuable for virtualisation and VDI deployments where multiple virtual machines may contain large amounts of identical operating system and application data.

SMB, NFS and iSCSI Storage

The ES1686dc R2 supports major enterprise storage protocols including:

• SMB
• NFS
• iSCSI

This allows a single ES1686dc R2 to support both file-level and block-level storage requirements.

The system can therefore be deployed for enterprise file sharing, virtualisation, databases, application storage and other business-critical workloads.

Expandable Enterprise Storage

Storage capacity can be expanded beyond the 16 internal drive bays using compatible QNAP SAS expansion enclosures.

This provides a path for increasing storage capacity as business requirements grow without immediately replacing the primary storage platform.

The combination of SAS expansion and PCIe connectivity makes the ES1686dc R2 suitable for organisations expecting their enterprise storage requirements to increase over time.

Redundant Enterprise Hardware Architecture

The ES1686dc R2 incorporates multiple technologies designed to minimise single points of failure, including:

• Dual active-active controllers
• Redundant hot-swappable power supplies
• Dual-path SAS
• ECC memory
• Multiple network interfaces
• Hot-swappable drives
• Cache-to-Flash protection
• Battery-protected write cache

This makes the ES1686dc-R2 significantly different from a conventional single-controller rackmount NAS and particularly appropriate for applications where storage availability is critical.

3U Enterprise Rackmount Design

The ES1686dc-R2 is housed in a 3U rackmount chassis designed for installation in professional server rooms and data centres.

Its 16 front-accessible hot-swappable drive bays provide convenient access for drive replacement and storage maintenance.

The rackmount architecture combines high storage capacity with the serviceability, redundancy and connectivity required for enterprise deployments.

Ideal Applications for the QNAP ES1686dc-R2-2123IT-64G

The ES1686dc-R2-2123IT-64G is particularly well suited to:

• Enterprise virtualisation
• Virtual Desktop Infrastructure
• Enterprise databases
• High-availability file servers
• iSCSI storage
• Private cloud infrastructure
• Business-critical applications
• Data centre storage
• Enterprise backup
• Disaster recovery
• High-capacity SAS storage
• SAS SSD storage
• Shared application storage
• Organisations requiring dual-controller high availability

Technical Specifications

Specification	Details
Model	QNAP ES1686dc-R2-2123IT-64G
Product Family	ES1686dc R2
Product Type	Dual-Controller Enterprise ZFS NAS
Form Factor	3U rackmount
Controller Modules	2
Controller Architecture	Dual active-active
CPU	2 × Intel Xeon D-2123IT
CPU per Controller	4-core
CPU Frequency	2.20GHz, burst up to 3.0GHz
CPU Architecture	64-bit x86
Encryption Engine	AES-NI
Total Installed Memory	64GB DDR4 ECC
Memory per Controller	32GB RDIMM DDR4 ECC
Memory Configuration per Controller	4 × 8GB
Maximum System Memory	1TB
Maximum Memory per Controller	512GB
Memory Slots	16 total / 8 per controller
Flash Memory	4GB dual-boot OS protection
Drive Bays	16 × 3.5-inch
Drive Interface	SAS 12Gb/s, backward compatible with SAS 6Gb/s
3.5-inch SAS HDD	Supported
2.5-inch SAS HDD	Supported
2.5-inch SAS SSD	Supported
Hot-Swappable Drives	Yes
SSD Cache Acceleration	Supported
L1 ARC Read Cache	RAM
L2 ARC Read Cache	SSD
ZIL Write Cache	NVRAM with C2F
Cache-to-Flash	1 × 64GB M.2 SSD per controller
10GbE	4 × 10GbE SFP+ per controller / 8 total
Ethernet RJ45	3 per controller
Remote Management	Dedicated interface per controller
PCIe Expansion	2 × PCIe Gen3 x8 per controller / 4 total
SAS Expansion	Supported
Operating System	QNAP QES
File System	ZFS
Storage Protocols	SMB, NFS and iSCSI
Inline Deduplication	Yes
Inline Compression	Yes
Snapshots	Yes
SnapSync	Yes
Power Supply	Redundant hot-swappable
Power Supply Rating	770W
Operating Temperature	0°C to 40°C
Operating Humidity	5–95% RH non-condensing

ES1686dc-R2-2123IT-64G vs ES1686dc-R2-2142IT-96G

The ES1686dc-R2-2123IT-64G provides the same core dual-controller SAS storage architecture as the higher-specification 2142IT models, but with a lower processor core count and less factory-installed memory.

Feature	ES1686dc-R2-2123IT-64G	ES1686dc-R2-2142IT-96G
CPU per Controller	Xeon D-2123IT	Xeon D-2142IT
CPU Cores per Controller	4	8
CPU Base Frequency	2.20GHz	1.90GHz
Maximum Burst	3.0GHz	3.0GHz
Total Installed Memory	64GB	96GB
Memory per Controller	32GB	48GB
Maximum Total Memory	1TB	1TB
Controllers	Dual active-active	Dual active-active
Drive Bays	16 × 12Gb/s SAS	16 × 12Gb/s SAS
10GbE SFP+	8 total	8 total
QES / ZFS	Yes	Yes

The ES1686dc-R2-2123IT-64G is therefore the entry configuration in the ES1686dc R2 family, retaining the key high-availability storage architecture while providing a more cost-effective processor and memory configuration for workloads that do not require the additional compute resources of the Xeon D-2142IT models.

Why Choose the QNAP ES1686dc-R2-2123IT-64G?

The QNAP ES1686dc-R2-2123IT-64G brings enterprise dual-controller high availability and ZFS data protection to organisations that do not require the higher processor and memory specifications of the 96GB and 128GB models.

Each controller includes an Intel Xeon D-2123IT 4-core 2.20GHz processor and 32GB DDR4 ECC memory, providing 64GB total factory-installed memory while retaining expansion capability up to 1TB across the system.

Sixteen 12Gb/s SAS bays provide flexible support for high-capacity enterprise SAS HDDs or high-performance SAS SSDs, while eight integrated 10GbE SFP+ interfaces provide substantial network bandwidth for virtualisation, databases and shared storage.

QES adds ZFS snapshots, SnapSync replication, inline deduplication and compression, while the dual active-active controllers, redundant power, dual-path SAS and Cache-to-Flash architecture provide the resilience required for critical business storage.