Block and object storage are two common types of data storage used in computing and cloud environments. Block storage divides storage into evenly sized blocks which are then mapped to servers, while object storage manages data as objects that contain the data, metadata, and an identifier. Both have their advantages depending on the use case.
What is Block Storage?
Block storage divides storage space into evenly sized blocks or volumes, each of which functions as an individual hard drive. Each block can then be mapped to individual servers to provide dedicated storage. Block storage is commonly used for:
- Operating system drives
- Database storage
- Transactional systems requiring fast, consistent performance
- Workloads needing direct, low-latency access to storage
Some examples of block storage services and solutions include:
- Amazon Elastic Block Store (EBS)
- Azure Managed Disks
- Google Persistent Disk
- VMware vSphere Virtual Volumes (vVols)
- Dell EMC Unity
- NetApp ONTAP
What is Object Storage?
Object storage manages data as objects in a flat structure instead of blocks. Each object includes the data, metadata describing the data, and an identifier unique to each object. Object storage has advantages for:
- Storage of large unstructured data such as video, images, audio files
- Big data analytics
- Backups and archives
- Distributed, scaled environments
Some examples of object storage solutions include:
- Amazon Simple Storage Service (S3)
- Microsoft Azure Blob Storage
- Google Cloud Storage
- Oracle Cloud Object Storage
- DigitalOcean Spaces
- Alibaba Cloud Object Storage Service (OSS)
- IBM Cloud Object Storage
Key Differences
There are several key differences between block and object storage:
| Block Storage | Object Storage |
| Data stored in fixed sized blocks | Data stored as variable sized objects |
| Optimized for transactional workloads requiring fast access | Optimized for storing large files, such as video and images |
| Lower latency access to data | Higher latency than block storage |
| Limited scalability, blocks allocated upfront | Highly scalable into petabytes of storage |
| File system with folder hierarchy | Flat structure with no hierarchy |
| More expensive per GB than object storage | Lower cost per GB stored than block storage |
In summary, block storage is best for performance-sensitive workloads while object storage suits large-scale data that does not require file heirarchy.
Block Storage Use Cases
Here are some common use cases where block storage provides advantages over object storage:
Database Storage
Databases require high IOPS (input/output operations per second), low latency, and consistency for optimal performance. Block storage like AWS EBS and Azure Premium SSD provide these capabilities to support demanding database workloads.
Transactional Applications
Applications conducting many transactions like banking systems and ERPs need fast access to storage. The high performance of block storage makes it well suited for supporting transactional systems.
Boot Volumes
Block storage volumes provide fast, dedicated storage for booting operating systems quickly. Block storage can also be replicated for high availability.
Server Virtualization
In virtualized environments, block storage allows abstraction from the underlying storage hardware to present shared storage pools to virtual machines (VMs). This enables features like live migration of VMs between hosts.
Object Storage Use Cases
Here are some top use cases where object storage provides benefits:
Backup and Archival
The vast, inexpensive capacity of object storage makes it ideal for backups and archives. Data can be stored across multiple locations for redundancy and is retained for long periods.
Big Data Analytics
The scalability of object storage suits big data storage and analytics using tools like Hadoop and Spark. Massive datasets can be stored and analyzed cost-effectively.
Content Distribution
Object storage can serve large volumes of static content like videos, images, and audio files to globally distributed users with low latency. Content delivery networks leverage object storage’s geographic distribution capabilities.
Hybrid Cloud
Object storage supports seamless data transfer across cloud providers and on-premises environments. This hybrid model provides flexibility, scalability and data portability.
Comparing AWS S3 and EBS
AWS provides two popular block and object storage services: Amazon Elastic Block Store (EBS) and Simple Storage Service (S3). Here is a comparison:
| AWS EBS | AWS S3 |
| Block storage volumes mounted like hard drives | Object storage accessed via REST APIs or HTTP |
| Persistent storage directly attached to EC2 instances | Shared storage not attached to instances |
| Lower latency, higher performance | Higher latency object-based storage |
| Limited scalability, fixed capacity per volume | Massive scalability into exabytes |
| Snapshots for backups and replication | Replication across regions for redundancy |
| More complex management | Simpler to manage at scale |
In summary, EBS provides high performance block volumes for EC2 instances, while S3 is better for large-scale object storage accessible across the AWS cloud.
Comparing Azure Disks and Azure Blob Storage
Similarly, Microsoft Azure provides Azure Disks for block storage and Azure Blob storage for object storage:
| Azure Disks | Azure Blob Storage |
| Block-level storage volumes for VMs | Scalable object storage for unstructured data |
| Persistently attached to Azure VMs | Accessible via HTTP/HTTPS |
| Lower latency, higher throughput | Higher latency object storage |
| Limited scalability, fixed volume sizes | Virtually unlimited capacity |
| Local disk redundancy options | Geo-redundant storage across regions |
| Suited for transactional workloads | Ideal for large files, backups, archives |
Azure Disks provides dedicated block storage volumes for Azure VMs, while Blob storage offers highly scalable data storage and retrieval.
Conclusion
Block and object storage provide complementary strengths for different workloads. Block storage excels at transactional applications requiring high performance, while object storage provides scalable, inexpensive storage for large datasets. AWS, Azure and other cloud providers offer both block and object storage options to build optimal solutions for a range of use cases.
