Block storage is critical in data storage because it provides companies with a scalable, robust virtualization and cloud computing solution. This technology is becoming increasingly crucial as digitization increases, and the amount of data to be stored continues to grow.
Virtualization technologies like VMware allow multiple virtual servers to run on physical hardware, creating a significant demand for flexibly distributable storage. At the same time, many companies are migrating their infrastructure and applications to the cloud to save costs and become more agile. Cloud platforms like Amazon AWS (Amazon Web Services) and Microsoft Azure also rely on block storage to dynamically store and scale virtual servers and containers independently of physical resources.
This article first explains block storage and how it works, then describes the differences between block storage and other storage technologies, such as file or object storage. Additionally, it highlights the benefits of block storage for virtualization and cloud use. Finally, leading providers of block storage solutions, such as NetApp, are discussed. The goal is to provide you with a comprehensive understanding of this essential storage technology and its significance for modern IT infrastructure.
Block storage is a technology in which digital data is divided into blocks of a fixed size, or "storage blocks." Each block has a unique logical address and a defined size, typically ranging from 512 bytes to 4 KB.
These blocks are stored independently on mass media like hard drives or solid-state drives (SSDs). The division into blocks allows data to be managed flexibly and independently of the hardware.
Virtual host bus adapters (vHBA) and storage controllers can dynamically allocate individual blocks to operating systems or virtualization containers (such as VMware ESXi or KVM). The virtual systems address the blocks using logical block addresses and access the content directly without an intervening file system structure.
This decentralized access to individual blocks allows block storage to adjust storage resources to application requirements optimally and, for example, dynamically allocate additional blocks to virtual machines when more capacity or performance is needed. The independent access to each block also enables high scalability and parallel use of resources.
In this section, we examine the differences between block storage and both file and object storage.
The most significant difference between block storage and file or object storage is how data is accessed.
In contrast, block storage accesses individual, fixed-address blocks independently of the hardware and without an overarching system structure. Each block only has a logical block address and is managed independently of others. This allows for particularly high flexibility and scalability, as individual blocks can be freely distributed between applications and machines without regard to a file system or object model.
Block storage is particularly suitable for workload-intensive applications, such as virtualized infrastructures or databases, where high IOPS and low latencies are critical. The very simple and hardware-adjacent access to individual blocks enables exceptionally efficient use of storage resources. On the other hand, file and object storage is more suitable for use cases with an inherent file or object structure, such as file servers, media repositories, or cloud storage.
Data is first physically divided into equal-sized blocks in block storage and stored on mass storage devices like hard drives or solid-state drives (SSDs).
Through Logical Volume Management (LVM), individual physical blocks can be aggregated into larger logical units. LVM provides redundancy and allows elastic scaling.
These volume groups consisting of logical blocks are called logical block devices. They provide an abstract view of the physical storage for the operating system or virtualization software.
Storage controllers and virtual host bus adapters (vHBA) manage access to these logical block devices. They translate the requests from VM (virtual machines) hypervisors or cloud environments like VMware ESXi, KVM, or OpenStack into native block accesses to the mass storage devices.
Hypervisors and container orchestrators can dynamically assign individual logical block devices to operating systems or applications independently of the hardware. They address the blocks using their logical block addresses and use the storage directly and efficiently without file system overhead. Changes in the assignment are possible at any time.
The critical advantage of block storage is hardware independence. Since data is accessed not via file names or identifiers but independently of hardware via addresses, block devices can be moved and virtualized at will.
Additional advantages include:
NetApp specializes in block storage. NetApp offers robust block storage systems for virtualization and cloud environments with FAS, AFF, and E-Series solutions.
NetApp block storage with Cloud Volumes ONTAP
Cloud offers excellent block storage options, although some native enterprise features are unavailable. Cloud Volumes ONTAP extends the block storage offerings on AWS, Azure, and Google Cloud with industry-leading ONTAP data management features for data protection, mobility, cost optimization, and more.
NetApp supports on-premises implementations and public cloud solutions through unified data storage. Data can be provided transparently and securely across protocol endpoints, enabling hybrid cloud scenarios, and laying the foundation for modern, flexible IT infrastructure.