Block-based cloud storage services provide logical management of storage volumes over a virtualized storage network, with a web-based service interface.
Cloud-based mass storage services allow you to add a logical drive of a specific size and capacity to any cloud virtual machine. This cloud storage volume can only be accessed by the cloud VM using low-level hard drive access protocols.
Cloud block storage must be provisioned prior to use. Depending on its performance objectives, for example, for use in databases or file systems, it can support a specific number of Input/Output Operations Per Second (IOPS). Most cloud providers adjust pricing based on the number of IOPS available for use with their block storage volumes.
Block Storage in the Cloud: Benefits and Challenges
Block storage is a veteran and popular storage type, still supported by many applications. Large-scale block storage was traditionally associated with a local Storage Area Network (SAN), but it is now an important part of the cloud environment.
Block storage benefits Block storage uses blocks of fixed size when storing data on media. Blocks get their own unique address that helps identify individual blocks. These addresses are the only metadata for the block.
Because the blocks do not contain metadata, they are small and efficient, and do not require major overhead to manage. A separate software program, independent from storage media, manages the location and configuration of blocks on storage devices. Additionally, the software can retrieve data, using addresses to identify the relevant blocks, and organizing data into files.
Block storage is a solution of choice for enterprise storage systems, due to their advantages in speed, performance, flexibility, low I/O latency, and high reliability. Physical storage media is easy to remove and transport, and is based on technology that is well known and widely used, supporting a very wide range of applications.
Block storage challenges Block storage is not without its challenges. Limited scalability, for example, and an increase in latency, may occur when the controlling software is not collocated with the storage devices.
Another critical challenge is the lack of metadata. This means the management application has to feed additional request information—and do this for each block. Furthermore, storage media is expensive and requires specialized skills to maintain and optimize.
Despite these challenges, block memory is sufficient for many business scenarios. It is especially suitable for high-performance applications. For example, block storage is effective for mission-critical workloads, such as virtual machines, mail servers, and relational databases, that need to balance high I/O performance with low latency. You can also leverage block storage for RAID arrays.
Cloud Block Storage Options
AWS Block Storage
Amazon Elastic Block Store (Amazon EBS) is a cloud-based block storage service. While EBS can be applied to a range of use cases, it is often chosen for data storage on Amazon Elastic Compute Cloud (EC2), Amazon's popular cloud-based virtual machine service.
Amazon EBS can support different types of data, including software applications, containers, big data engines, databases, and file systems. To avoid data loss, EBS volumes are replicated between three availability zones (AZ). EBS snapshots can be used to backup latest changes. EBS allows users to change drive type and size on an ongoing basis to optimize performance.
Azure Block Storage
Azure provides a managed disks service for block volumes, which you can use with Azure Virtual Machines (VMs). Managed disks work similarly to how physical disks work in on-premise servers, except that managed disks are virtual. Managed disks enable you to specify disk size and type, and then provision the disk. Once the disk is provisioned, Azure manages the rest.
When using Azure managed disks, you can choose between several disk types, ranging from regular standard hard disk drives (HDD) and standard solid-state drives (SSD), and including premium SSDs and ultra-disks.
Zonal Persistent Disks Persistent Disks are network-attached persistent storage devices that can be accessed from a virtual machine on Google Compute Engine. The data on each Persistent Disk is spread across multiple physical drives. Compute Engine manages data and physical disk allocation for optimal redundancy and performance.
Persistent disks exist independently of virtual machine instances. So even if an instance is deleted, you can detach the Persistent Disk to preserve the data. Google increases disk performance automatically with disk size, and lets users resize disks on an ongoing basis.
Regional persistent disks Regional Persistent Disks are similar to Zonal Persistent Disks, but they provide continuous data storage and replication between two zones in the same Google Cloud region. Regional Persistent Disks perform synchronous replication between regions, offering very high availability. Regional Persistent Disks can also work with regional managed instance groups in Google Compute Engine.
Cloud Block Storage with NetApp Cloud Volumes ONTAP
NetApp Cloud Volumes ONTAP, the leading enterprise-grade storage management solution, delivers secure, proven storage management services on AWS, Azure and Google Cloud. Cloud Volumes ONTAP supports up to a capacity of 368TB, and supports various use cases such as file services, databases, DevOps or any other enterprise workload, with a strong set of features including high availability, data protection, storage efficiencies, Kubernetes integration, and more.
Cloud Volumes ONTAP supports advanced features for managing SAN storage in the cloud, catering for mission-critical, block-storage-based workloads as well as file shares.
In particular, Cloud Volumes ONTAP provides high availability, ensuring business continuity, and supports built-in storage efficiency features, including thin provisioning, data compression, deduplication, and data tiering, reducing storage footprint and costs by up to 70%.