Object storage vs. block storage
Object storage and block storage are two storage architectures that differ significantly in structure, access, and purpose. The key difference between object storage and block storage is that the former stores data as objects with metadata via an API, while the latter divides data into addressable blocks managed directly by the operating system.
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What are object and block storage?
Object storage is a modern storage architecture where data is stored as objects. Each object consists of the actual data, metadata, and a unique identifier. These objects are stored in a flat namespace. This means that all stored objects are organized at the same level. There is no hierarchical structure like folders or directories, like in file systems. The data objects in object storage are typically accessible via an HTTP-based API.
Block storage on the other hand divides data, as the name suggests, into equally sized, fixed blocks each with a unique address. Each block includes only the raw data, without additional metadata or context information. The system accessing this data—usually an operating system or a virtualization platform—is responsible for interpreting the structure and meaning of the stored data. From the operating system’s perspective, block storage behaves like a physical hard drive or SSD: It can be partitioned, formatted, and used for various applications.
Object vs. block storage at a glance
In the following table, you’ll find an overview of the main differences of “Object storage vs. block storage” in direct comparison:
| Feature | Object Storage | Block Storage |
|---|---|---|
| Data Structure | Objects with Metadata | Data Blocks without Context |
| Access | HTTP(S) (REST APIs) | Directly through the Operating System |
| Latency | High | Low |
| Scalability | High (ideal for Cloud) | Limited, mostly local or via SAN |
| Metadata | Extensive, User-Defined | Barely or Not Present |
| Use Cases | Backups, Media, Big Data | Databases, Operating Systems, VM Disks |
| Cost | Cheaper per TB for large data volumes | More expensive, especially for high-performance systems |
| Flexibility | Good for unstructured, infrequently accessed data | Good for structured, frequently accessed data |
How object and block storage work
Object storage saves data as three-part objects:
- actual user data (e.g., an image or a video)
- metadata (additional information like creation date, file type, or custom tags)
- unique key serving as an address
These objects are stored in a flat namespace. Technically, this is simpler and more scalable because there’s no need to manage a complex directory structure. Access is via the HTTP protocol, usually through REST. APIs. Applications interact with the storage like a web service. Many cloud services, such as Amazon S3 or Google Cloud Storage, are based on this technology. Object storage can be distributed worldwide, allowing data to reside at multiple locations simultaneously. This enhances both fault tolerance and global availability.
Block storage functions more like a traditional drive or hard drive. Here, data is divided into equally sized blocks, each assigned an address. These blocks contain no metadata. This means it’s the responsibility of the operating system or an application on top (e.g., a file system or a database) to know which blocks belong together. Block storage is often provided via a Storage Area Network (SAN) or through the iSCSI network protocol. The storage then appears to the operating system like a local drive and can be partitioned, formatted, and written to normally.
Differences and similarities between object storage vs. block storage
Although object storage and block storage both serve data storage purposes, they fundamentally differ in structure, access, and usage. The biggest difference lies in how data is organized. In terms of latency and performance, block storage has a few advantages because it allows for fast, block-level access. Object storage, on the other hand, excels in scalability and long-term data retention.
Both storage types share the fact that they are often used in cloud environments and, through their respective specializations, can efficiently support different workloads. Both can be part of a hybrid storage approach. Also, in terms of reliability and fault tolerance, modern implementations of both technologies offer important mechanisms like replication and redundancy. While block storage is more performance and direct-control oriented, object storage offers a flexible and cost-effective solution for large data volumes. In modern IT environments, both types of storage are often combined to make the most of their respective advantages.
Typical use cases
Use cases for object storage
Object storage is frequently used for backup and archiving solutions. Its high scalability and cost-effective storage make this storage solution ideal for long-term data retention. It’s also popular in content delivery networks (CDNs), as large media files can be easily and efficiently distributed.
Another important use case is the storage of big data, such as log files, sensor data, or video recordings, since the objects can be stored and processed independently. Modern web apps and mobile applications also use object storage to store user files, images, and documents.
Use cases for block storage
Block storage is the preferred solution for databases and transactional systems. The ability to directly access blocks ensures high performance and low latency. These characteristics are especially important for applications that require frequent reading and writing of data at the same time.
Virtual machines and operating systems also benefit from using block storage, as they rely on fast and reliable storage. Even in traditional data centers, where deterministic performance is crucial, block storage is still widely used.
In addition to object storage and block storage, there is another storage architecture called file storage. This type of storage organizes data as usual in folders and files. File storage is particularly suitable for shared network drives or traditional file systems. Learn more about the differences in our article “Object storage vs. file storage.”
Advantages and disadvantages
In a direct comparison of object storage vs. block storage, the advantages and disadvantages play an important role.
Object storage offers high scalability, easy integration through web APIs, and the ability to store extensive metadata for each object. This makes it particularly well-suited for unstructured data and cloud-native applications. However, access is comparatively slow, so object storage is not as suitable for applications where low latency is important.
Block storage, on the other hand, offers significantly lower latency and particularly impressive performance. The direct integration with virtual machines or containers also makes block storage the first choice for traditional IT infrastructures. However, this comes with higher costs and less flexibility in handling large, distributed data sets.