JBOD (Just a Bunch of Disks)

JBOD stands for “Just a Bunch of Disks.” It describes a storage setup where multiple hard drives or SSDs are grouped in a single enclosure or system without any RAID configuration. Each disk operates independently and is recognized by the host system as a separate volume. JBOD provides raw, uncombined storage capacity without built-in redundancy or performance tuning. It is one of the most basic forms of disk aggregation and is used in various computing environments, including file servers, media servers, backups, and entry-level hosting platforms.

The JBOD approach is simple. It prioritizes storage flexibility and ease of use over speed, fault tolerance, or data protection. As a result, JBOD systems often rely on external software for tasks such as data replication, error recovery, or volume management.

Early Usage and Development

The concept of JBOD (Just a Bunch of Disks) emerged during the 1990s as data centers and server farms expanded. At the time, storage systems needed simple ways to increase capacity without the complexity or cost of RAID. While RAID offered redundancy and performance, it also required:

• Identical or closely matched drives
• Additional processing overhead
• More complex setup and management

In contrast, JBOD allowed administrators to:

• Use any available drive, regardless of size or model
• Add capacity quickly and affordably
• Avoid the performance penalty and rigidity of traditional RAID

JBOD systems became popular for:

• Non-critical data storage
• Backup and archival purposes
• Scenarios where redundancy wasn't essential

In contrast to RAID, which combines multiple disks into one logical volume, JBOD keeps each disk as a separate entity. Some implementations allow combining drives into a single volume using linear concatenation, but this is not the default behavior and does not provide any redundancy.

As operating systems and software-defined storage technologies matured, JBOD configurations gained new flexibility. Tools like:

• Linux Logical Volume Manager (LVM)
• Windows Storage Spaces
• ZFS

enabled administrators to treat JBOD arrays as dynamic storage pools, layering advanced features like snapshots, compression, and tiering—without requiring RAID at the hardware level.

Today, JBOD continues to be a useful option for low-cost, high-capacity storage needs, especially when paired with intelligent software.

How JBOD Works

In a JBOD configuration, multiple physical drives are connected to a host system. Each disk is mounted and accessed separately unless combined through software. There are two main ways JBOD is used:

• Pure JBOD: Each disk appears as its own logical volume. The system does not combine or span data across drives. This is the default mode in most operating systems when connecting multiple unconfigured disks.
• Spanned JBOD (Linear Volume): Some systems allow disks to be joined into a single large volume by writing data sequentially across the drives. This configuration does not provide redundancy and is not fault-tolerant. If one disk fails, the entire volume may become unreadable.

Unlike RAID, JBOD does not mirror, stripe, or add parity to data. It does not improve performance through parallelism or protect against disk failure. Each drive in the system must be managed independently unless wrapped in a higher-level file system or software layer.

JBOD vs. RAID

RAID (Redundant Array of Independent Disks) groups multiple drives into one logical volume using specific layouts for redundancy or speed. For example, RAID 1 mirrors data across drives for fault tolerance, while RAID 0 stripes data for speed.

In contrast, JBOD offers no redundancy or performance benefits by default. The advantage is flexibility. Any type or size of disk can be added to the system. The drives do not need to match in capacity or speed, and they can be used or removed individually.

JBOD is simpler and easier to manage in certain cases. It does not require complex controller settings or RAID metadata. However, it relies on the operating system or storage software to provide backup, replication, or recovery features.

Use Cases

JBOD is used in a variety of situations where raw storage capacity is more important than performance or redundancy.

• Backup Systems - JBOD is often used for storing scheduled backups. Since backup data can be replicated or stored off-site, the lack of redundancy is not a major concern. Drives can be rotated or archived easily.
• Media Archives - When storing large video, image, or audio collections, JBOD allows inexpensive scaling. Each drive can be dedicated to a specific type of content or project.
• Cold Storage - JBOD works well for infrequently accessed data. It allows administrators to use low-cost disks without configuring RAID. Drives can be spun down when not in use to save power.
• Entry-Level Hosting - Some hosting providers use JBOD for simple file hosting services or non-critical content. By layering a file system like ZFS or Btrfs over JBOD, administrators can add snapshots, checksums, and replication.
• Testing Environments - Developers use JBOD for test setups, software builds, or temporary storage. The simplicity makes it easy to add or remove drives without complex configuration.

Advantages

• Simplicity - JBOD systems are easy to set up. There are no RAID levels to choose or metadata to manage. Drives are recognized and used individually.
• Flexibility - Different drive sizes and types can be mixed. This is useful when repurposing old hardware or working with leftover components.
• Cost-Effective - There is no need for hardware RAID controllers or matched drive sets. JBOD enclosures are often cheaper than RAID-enabled alternatives.
• Independent Drive Access - Each disk can be removed and read on another system. This makes data migration and recovery easier, as drives do not depend on RAID metadata.
• Compatibility with Software RAID or File Systems - JBOD can serve as the base layer for software-defined storage, allowing administrators to apply custom redundancy or volume policies using tools like LVM, ZFS, or Btrfs.

Limitations

• No Redundancy - If a disk fails, the data on that disk is lost. In spanned configurations, failure of one disk can corrupt the entire logical volume.
• No Performance Gain - JBOD does not offer speed improvements. RAID 0 or RAID 10 provide better performance through data striping.
• Manual Management - Each drive must be monitored and managed separately. Backups, replication, and error checking must be handled at the file system or application level.
• Scalability Issues - As the number of drives increases, managing them individually becomes more complex. Without automation, this adds to the administrative burden.
• Power and Cooling - JBOD enclosures can contain many drives, which require proper power distribution and cooling. This may limit deployment in small spaces.

JBOD Hardware

JBOD hardware usually comes in the form of an enclosure with power supplies, fans, and a backplane. It connects to a host system via SATA, SAS, or other interfaces. The host sees each disk individually. These enclosures range from small desktop units with 4 drives to rack-mounted systems that hold 48 or more drives.

Many JBODs include management features such as:

• Hot-swappable bays
• Drive LEDs
• Temperature and fan monitoring
• Redundant power supplies

They do not include RAID controllers or onboard processors. This makes them lighter and easier to integrate into custom software stacks.

JBOD vs. JBOF

While both terms share a similar name and design idea, their focus differs.

• JBOD uses spinning disks or SATA SSDs and is usually connected over SAS or SATA interfaces.
• JBOF uses NVMe SSDs and connects over PCIe or NVMe over Fabrics, offering much higher speed and density.

JBOD serves lower-cost, lower-performance roles. JBOF targets high-speed, enterprise storage needs.

JBOD in Hosting Environments

In hosting platforms, JBOD is usually used where cost matters more than performance or resilience. It serves as storage for:

• Static content
• Archived logs
• Secondary backup layers
• Testing or development sites

At NTC Hosting, we have tried using a JBOD Cluster for our main storage solution, but it was not cost-effective. We have since switched to a JBOF, which is superior to JBOD in almost every way and presents meaningful improvement for customers using our web hosting plans.