JBOF (Just a Bunch of Flash)

JBOF, short for "Just a Bunch of Flash," refers to a storage architecture that connects multiple flash storage devices—usually NVMe SSDs—into a single enclosure without built-in compute resources. Unlike traditional storage arrays with embedded processing or RAID controllers, a JBOF simply houses flash drives and provides high-speed access to them through external connections such as PCIe or NVMe over Fabrics (NVMe-oF).

This design focuses on maximizing performance and density while keeping the system flexible and modular. JBOF is commonly used in data centers, web hosting, cloud storage systems, and high-performance computing environments.

Origins and Context

The term JBOF (Just a Bunch of Flash) evolved from the earlier concept of JBOD (Just a Bunch of Disks). JBOD systems were simple storage enclosures designed to house many spinning HDDs, typically connected via SAS or SATA. These systems:

• Focused on adding raw storage capacity
• Did not include RAID controllers or storage virtualization
• Relied on external servers for logic and management

As SSDs, especially NVMe drives, began replacing HDDs in performance-critical environments, the storage model evolved into JBOF. Key characteristics of JBOF systems include:

• Use of NVMe SSDs instead of spinning disks
• No built-in storage processors - control is handled by external compute nodes
• Emphasis on speed, efficiency, and simplicity

The underlying technology that enabled this shift was NVMe over PCIe, which:

• Allows SSDs to connect directly to CPUs using PCIe lanes
• Bypasses traditional storage controller bottlenecks
• Supports remote access to storage over high-speed links like RDMA or NVMe over Fabrics (NVMe-oF)

JBOF systems are now used in environments where low latency, high throughput, and dense storage are critical, such as cloud infrastructure, hyperscale data centers, and high-performance computing.

Hardware Architecture

A JBOF contains several key components:

• Enclosure chassis - A rack-mounted unit (typically 1U to 4U) that holds SSDs. High-density JBOFs can hold 24, 48, or more NVMe drives in a single chassis.
• Backplane - A circuit board that connects all the SSDs to the external ports. Unlike JBODs that use SAS expanders, JBOFs route PCIe lanes to each drive or to a switching component.
• PCIe switch - Some JBOFs use PCIe switches to allow a single upstream host to access multiple drives. Others use fabric-based connectivity, such as NVMe-oF, to connect to many hosts.
• Cooling and power systems - High-performance SSDs generate heat, so efficient airflow and redundant power supplies are standard features.
• Management interface - While a JBOF has no built-in compute logic, it usually includes a baseboard management controller (BMC) for remote monitoring and basic control tasks.

JBOFs do not include RAID controllers, volume managers, or storage processors. These tasks are handled externally by connected servers or software-defined storage (SDS) systems.

Use in Modern Infrastructure

In web hosting, content delivery, and high-volume transactional environments, JBOFs play a central role. Their design aligns with a disaggregated storage model, where compute and storage scale independently.

A server can connect to one or more JBOFs and use the flash devices directly. This allows flexible resource allocation. If more storage is needed, a new JBOF can be added without replacing or expanding the compute layer.

JBOFs are often paired with software like

• Ceph or GlusterFS for distributed storage clusters
• Kubernetes CSI drivers for persistent volume management
• SPDK (Storage Performance Development Kit) for low-latency user-space access
• ZFS or btrfs for volume management and data integrity

This model suits service providers who need to scale infrastructure on demand. For example, a cloud provider may run virtual machines or containers on compute nodes that access shared NVMe storage over NVMe-oF using JBOFs.

Comparison with Other Storage Models

• JBOF vs. JBOD - While JBODs house spinning disks and connect using SATA or SAS, JBOFs use NVMe SSDs and connect via PCIe or NVMe-oF. JBOFs deliver much higher throughput and lower latency.
• JBOF vs. DPU/RAID-based Arrays - Traditional storage arrays often include built-in RAID processing, storage tiering, and deduplication. These features provide convenience but may introduce latency or limit scalability. JBOFs shift this processing to external systems, allowing fine-grained control and better performance tuning.
• JBOF vs. EBOF (Ethernet Bunch of Flash) - An EBOF is similar to a JBOF but includes an Ethernet switch and logic to expose flash devices over the network without an external host. EBOFs are more independent but less flexible in some configurations. JBOFs offer better control from the host side.

Key Benefits

• Performance - JBOFs provide direct access to NVMe SSDs. With minimal overhead, they deliver high IOPS and low latency. When connected via PCIe or NVMe-oF, bandwidth can exceed tens of gigabytes per second.
  This speed benefits workloads like:
  • Transactional databases
  • High-frequency web hosting
  • Real-time analytics
  • Large-scale caching systems
• Modularity - JBOFs separate storage from compute. This separation allows independent scaling and replacement. A hosting provider can expand storage by adding another JBOF without touching the application servers.
  This reduces cost over time. Instead of buying new storage nodes with embedded compute, administrators only add flash when needed.
• Cost Efficiency - By eliminating embedded RAID or storage processors, JBOFs reduce upfront costs. Providers can choose their own SDS software, create custom RAID layouts, or use erasure coding.
  This is especially useful in environments with custom needs or large-scale deployments. Hosting providers can use commodity SSDs and open-source tools to build tailored solutions.
• Density - Modern JBOFs support dozens of NVMe drives in a compact chassis. For example, a 1U JBOF might hold 24 hot-swappable SSDs. This design reduces rack space and simplifies cable management.
  Higher density means more capacity per server rack and better use of physical infrastructure.
• Shared Access - With proper switching and fabric protocols, a JBOF can serve multiple hosts. This makes it easier to run clusters of application servers that share access to a common pool of flash.
  In multi-tenant hosting or public cloud systems, shared access allows better utilization of fast storage.

Challenges and Considerations

• Complex Management - JBOFs require external software for drive provisioning, redundancy, and performance tuning. This increases the setup and maintenance work. Hosting companies need experience with SDS and PCIe fabric management to use JBOFs effectively.
• Compatibility - Because JBOFs rely on PCIe and NVMe, they must match host interfaces and drivers. Not all systems support external PCIe connections or NVMe over Fabrics. Careful planning is needed to ensure end-to-end support.
• Redundancy Planning - JBOFs themselves often have redundant power and fans, but they lack RAID or data protection. These must be implemented externally. Hosting providers use software RAID, replication, or distributed file systems to protect data.
• Cooling and Power - High-density JBOFs with dozens of NVMe drives can draw significant power and produce heat. They need proper rack design, airflow planning, and monitoring.

Typical Use Cases

• Web hosting clusters: Shared flash storage improves access to site content and user data.
• Database backends: JBOFs support high-speed random access for large transactional workloads.
• VM or container storage: Centralized flash pools reduce overhead and speed up deployment.
• Media servers: Streaming systems benefit from fast, shared flash access.
• AI and machine learning: Fast scratch space for large datasets during training and inference.

JBOF and NTC Hosting

JBOF (Just a Bunch of Flash) configurations, particularly those utilizing NVMe technology, are increasingly popular in hosting environments for their ability to provide scalable, high-performance storage solutions. NVMe JBOFs enhance data throughput and reduce latency, making them ideal for handling large-scale data operations and high-traffic applications.

NTC Hosting integrates NVMe JBOFs across all its web hosting plans, providing amazing performance without the complexities of operating a whole server. This integration ensures that customers benefit from superior data processing speeds and storage scalability, meeting the demands of modern, data-intensive web applications and services.