Block storage is used to store data files on Storage Area Networks (SANs) or cloud-based storage environments. It can be attached to compute instance. Block Storage normally mounted onto only one compute node at a time. With block storage, you specify the size of the storage and pay a fee based on the size you provisioned.

When data is moved to block storage, the underlying SAN technology breaks the data into separate, uniform-sized pieces, or blocks. Each block will be given a unique identifier. The SAN will then place those blocks onto the physical storage, distributing them across several disks, often making multiple copies.

When a user or application requests data from a block storage system, the underlying SAN technology reassembles the data blocks and presents the data to the user or application.

Block storage decouples data from user environments. It allows data to be spread and duplicated across multiple storage devices, enabling faster retrieval and higher resilience to disk failures.

Benefits:

Provides the lowest latency: Block storage provides the lowest latency for network-based storage versus local disk drives in the server, Provide IOPS up to 48,000 IOPS.

High performing: Block storage is highly available and independent of the clients that access it. It remains available and durable regardless of client outages.

High redundancy: Network-based block storage is considered to have a higher level of redundancy compared to local disk storage.

Endurance and Performance tiers: Block storage has two tiers from which to choose. Volumes can be created from 20 GB to 12 TB in size.

Eight authorized hosts: Block storage allows eight authorized hosts (can request up to 64) to connect via the multipath IO (MPIO) iSCSI connection.

Snapshots: Block storage allows point-in-time non-disruptive “snapshots,” which can be replicated to a cross-regional data center as a duplicate volume.

Custom costs: Block storage allows monthly and hourly billing cycles.

Data-at-rest encryption: Block storage offers provider-managed encryption-at-rest. Note: Customer-managed encryption is not supported by IBM Classic Storage; however, customer-managed encryption keys can be stored

Use Cases:

⦾ As you have learned, block storage has a high performance and is easily updatable. Therefore, many organizations use it for transactional databases.

⦾ Because of its high performance and reliability, block storage is a common solution for storing emails.

⦾ Block storage suitable for low latency workloads where consistently high speeds required.