EDSFF: The Next Generation Standard for Enterprise and Data Center Storage

Introduction: Meeting Modern Data Storage Challenges

In the rapidly evolving landscape of enterprise computing and data centers, storage technology must continuously adapt to meet escalating demands for performance, capacity, and efficiency. Traditional storage form factors such as 2.5-inch U.2 drives and M.2 SSDs have served the industry well, but as computing environments expand into new domains with more stringent requirements, these legacy formats have begun to reveal limitations in thermal management, power delivery, signal integrity, and density optimization.

Enter EDSFF (Enterprise and Datacenter Storage Form Factor) – a family of standards specifically designed to address these challenges and establish a foundation for next-generation storage solutions. Developed through collaboration among 15 leading technology companies and now maintained by the SNIA (Storage Networking Industry Association) as part of the SFF Technology Affiliate Technical Work Group (SFF TA TWG), EDSFF represents a comprehensive approach to storage form factor design optimized for modern enterprise environments.

The Evolution of Storage Form Factors

Legacy Storage Limitations

Before diving into EDSFF specifics, it’s important to understand the limitations of traditional storage form factors that prompted this development:

• 2.5-inch U.2 SSDs: Originally designed for rotating hard drives, these form factors weren’t optimized for flash memory density or thermal dissipation.
• M.2 SSDs: While compact, M.2 drives are limited in power delivery (typically 8.25W), lack hot-swap capabilities, and have thermal constraints.
• PCIe Add-in Cards: Though offering high performance, these cards consume significant space and aren’t ideal for high-density deployments.

EDSFF: A Purpose-Built Solution

EDSFF was conceived as a clean-slate approach, specifically engineered for modern flash storage and emerging storage class memory technologies. Rather than adapting legacy designs, EDSFF optimizes every aspect of the storage device form factor for data center and enterprise applications.

EDSFF Family: Form Factors and Specifications

The EDSFF family is built around a common connector standard originally derived from the Gen-Z Scalable Connector Standard. This connector provides significantly higher density than traditional PCIe slots, delivers 12V power (addressing a limitation of M.2), and offers excellent signal integrity for current and future PCIe generations.

E1 Series: Optimized for 1U Servers

The E1 series originated from Intel’s “Ruler” concept and is designed to fit vertically in 1U server chassis:

E1.S (Short)

• Design Focus: High-density storage in 1U servers
• Thickness Options: Multiple options (5.9mm, 9.5mm, 15mm, etc.)
• Enclosure Types: Available with bare PCB, heatspreader, or full enclosure
• Power Support: Up to 25W
• PCIe Lanes: Supports x4 to x8 lanes
• Advantages: Superior density and thermal management in 1U servers

E1.L (Long)

• Design Focus: Maximum capacity per drive in 1U servers
• Thickness Options: 9.5mm (25W) or 18mm (40W) heat sinks
• PCIe Lanes: Options for x4 or x8
• Capacity: Designed for drives with capacities of tens of TBs each
• Features: Hot-pluggable, front-access serviceable, integrated LEDs
• Advantages: Maximizes capacity per rack unit with superior serviceability

E3 Series: Versatile 2U Solutions

The E3 series is designed primarily for 2U servers and traditional enterprise deployments, offering greater compatibility with existing infrastructure while providing significant improvements:

E3.S (Short)

• Dimensions: 76mm height, 112.75mm length, 7.5mm width (thin) or 16.8mm (thick)
• Use Cases: Well-suited for NAND-based SSDs with x4, x8, or x16 PCIe link width
• Deployment: Primary form factor for server storage subsystems
• Versatility: Works across various platforms including modular and short-depth chassis

E3.S 2T (Short Thick)

• Use Cases: Optimized for Storage Class Memory (SCM) or front I/O implementations
• Note: One 2T (thick) device fits in two thin slots

E3.L (Long)

• Use Cases: High-capacity NAND-based SSDs or SCM devices
• Deployment: Primary form factor for storage subsystems and servers with deeper chassis

E3.L 2T (Long Thick)

• Use Cases: Ideal for FPGAs or accelerators

Technical Advantages of EDSFF

Enhanced Performance Capabilities

• Power Delivery: EDSFF supports up to 70W power output, far exceeding the 25W limit of traditional 2.5-inch SSDs and the 8.25W limit of M.2
• PCIe Lanes: Supports up to 16 PCIe lanes, enabling exceptional bandwidth
• Signal Integrity: Designed to support PCIe Gen 5 and Gen 6, with potential for future generations
• Interface Support: All EDSFF devices currently use the NVMe protocol over PCIe

Superior Thermal Management

• Purpose-Built Cooling: Form factor designs incorporate thermal considerations from the ground up
• Multiple Thickness Options: Different thickness variants accommodate various cooling solutions
• Optimized Airflow: Vertical orientation in E1 series improves airflow efficiency

Increased Density and Flexibility

• Space Efficiency: E1.S enables up to 36 drives in a 1U server, far exceeding traditional form factors
• Multi-Device Support: Beyond SSDs, the form factors support NICs, accelerators, and computational storage
• Standardized Connectivity: Common connector design facilitates mixed deployment of various devices

Enterprise-Grade Features

• Hot-Swap Capability: Fully hot-swappable design enhances serviceability
• Dual-Port Support: E3 family supports dual-port capability for high-availability applications
• Integrated Management: Features like built-in LEDs improve operational efficiency

EDSFF Integration and Ecosystem

Industry Adoption and Support

EDSFF has gained significant traction in the industry, with major hyperscale providers like Microsoft and Facebook incorporating these standards into their infrastructure. Dell Technologies and HPE have been leading proponents particularly of the E3 family for enterprise servers.

Compute Express Link (CXL) Integration

EDSFF form factors have been integrated into the Compute Express Link (CXL) ecosystem, highlighting their utility in high-performance computing environments. This integration enables EDSFF to support not just traditional storage but also advancing memory technologies that leverage CXL.

OCP NVMe Cloud SSD Specification

While not formally part of the EDSFF specifications, the Open Compute Project has developed the OCP NVMe Cloud SSD specification, which unifies requirements from major cloud providers and applies to M.2 22110, E1.S, and E1.L form factors. This specification helps reduce firmware customization requirements for different customers.

Application Scenarios for EDSFF

Hyperscale Data Centers

• High-Density Deployments: E1.S is ideal for hyperscale providers requiring maximum storage density
• Performance-Critical Applications: E3 series supports high-performance computing and analytics workloads
• Cloud-Native Infrastructure: Standardized form factors simplify procurement and deployment at scale

Enterprise Data Centers

• Traditional Enterprise Servers: E3 form factors offer a path forward for conventional enterprise deployments
• High-Availability Storage: Dual-port support in E3 series enables resilient storage architectures
• Mixed Workload Environments: Various thickness options accommodate different performance and thermal profiles

Edge Computing

• Space-Constrained Deployments: Compact form factors enable dense storage in edge locations
• Thermal Efficiency: Improved cooling capabilities support deployment in diverse environmental conditions
• Standardization: Common form factors simplify fleet management across core and edge environments

Future Outlook for EDSFF

Technological Evolution

As PCIe Gen 5 and Gen 6 become mainstream, EDSFF’s forward-looking design will enable seamless adoption of these high-speed interfaces. The form factor’s flexibility also positions it well for emerging technologies like CXL and computational storage.

Market Consolidation

While the EDSFF family currently includes numerous variants, market forces will likely drive consolidation around the most popular options, similar to what occurred with M.2 card sizes. This natural selection process will help simplify implementation decisions.

Expanded Application Domains

Beyond traditional storage, EDSFF is increasingly being adopted for other device types, including NICs, accelerators, and computational storage, reflecting its versatility as a general-purpose form factor for data center devices.

Wrapping up: EDSFF as the Foundation for Future Storage

EDSFF represents a significant leap forward in storage form factor design, addressing the limitations of legacy formats while establishing a foundation for future innovation. By optimizing for flash density, thermal management, serviceability, and performance, EDSFF enables more efficient, scalable, and powerful storage solutions for enterprise and data center environments.

As with any new standard, adoption will continue to evolve as the industry balances innovation with compatibility requirements. However, the comprehensive design approach and strong industry backing position EDSFF as the clear path forward for enterprise storage form factors in the coming years.

Major storage manufacturers including KIOXIA (formerly Toshiba Memory), Samsung, Intel, Micron, and Western Digital now offer EDSFF products, providing a growing ecosystem of compatible solutions across the E1 and E3 families.

The Bottom Line：For those looking to adopt EDSFF technology, carefully evaluate your specific requirements around density, performance, thermal constraints, and future expandability to determine which EDSFF variant best suits your environment.