Understanding the Differences Between File, Block, and Object Storage

Global data transmission and generation have reached unprecedented levels; IDC predicts that by 2025 the worldwide data sphere will expand to 163 ZB, a growth of over 1000% from 2016. This surge is driven by multiple factors.

Data sources and devices have multiplied—embedded systems and IoT devices collect data and feed it to big‑data applications for real‑time analysis. Continuous use of mobile phones, social media, online shopping, and countless apps generates massive daily data, while enterprises transform to deliver data to customers to satisfy the rising demand for unprecedented news and real‑time information.

According to Gartner, by 2020 more than half of major business processes and systems will incorporate some IoT element, and the volume of data generated, transmitted, and analyzed by big‑data applications will increase dramatically.

To meet storage demand, management and IT teams have significantly expanded solutions capable of handling and archiving far more digital content than before.

From a hardware perspective, not only are more storage devices (HDD, SSD, SSHD) required, but also an appropriate file system to manage the resulting data explosion. Even if not all data resides on devices, the most critical data and analysis results are stored there, driving higher storage space needs. Most of this demand is handled internally, though cloud services such as Amazon S3 or Microsoft Azure can also be used.

Traditional file‑storage and block‑storage concepts will no longer suffice for future data growth, for enterprises or cloud providers alike. The solution for storing massive data is object storage (also called object‑based storage). This article examines how object storage differs from earlier concepts and why it better accommodates the data explosion.

To understand the benefits of object storage, one must first grasp the older concepts of file storage and block storage, which differ significantly.

Differences Between File, Block, and Object Storage

File storage and block storage are methods of storing data on NAS and SAN systems.

In NAS systems, data is presented as a network file system. When a device attaches to a NAS, a mounted file system appears, allowing users to access files with appropriate permissions. NAS must manage user permissions, file locking, and other security measures so multiple users can access files, typically via NFS and SMB/CIFS protocols. This works well for hundreds of thousands or millions of files, but not for billions.

Block storage works similarly, but data is stored in blocks rather than files. Several blocks (e.g., in a SAN) combine to form a file. Each block has an address; a SCSI request to that address retrieves the block. The storage application decides where to place the block, and blocks carry no metadata about the storage system or application—they are simply raw data segments managed by SAN software. Block storage is often used for performance‑critical applications such as databases or transactions because data can be accessed, modified, and saved efficiently.

These two methods have performed well for years, yet a new concept is needed because both require user‑access control mechanisms for data modification.

Most newly generated data is static or unstructured, meaning the content does not change. This is where object storage shines:

In object storage, an object consists of data bound with its metadata (essentially a file). Each object receives a unique identifier calculated from its content and metadata, and applications reference objects via this ID. Many objects are stored on storage disks; in pure object storage, only one version of a file is kept. If a user modifies the file, a new version is stored as a new object. Consequently, object storage is ideal for backup, archiving, or storing large videos that are only viewed and not altered.

The key distinction is that the application supporting object storage manages the objects, eliminating the need for a traditional file system. Applications send queries to locate objects, which are assigned addresses within massive storage pools and stored there.

Because data management is simple—no real file system—object storage solutions scale more easily than file or block storage systems. Adding more disks expands capacity without extensive management overhead, a major advantage in an era of exponential data growth.

Thus, object storage is the perfect solution for handling massive data volumes and is heavily used by large cloud providers such as Amazon and Google. The article notes that data protection and recovery topics will be addressed in a second part.