Block, File and Object Storage
Choose where large bytes belong
Follow the responsibility
A database volume, a shared folder and a photo bucket are all storage, but they expose different ways to read and change bytes. Selecting one by price alone can leave the application without the operations it needs.
Keep metadata, such as a photo’s owner and visibility, separate from the media bytes when that makes the access pattern clearer. Storage permissions and publication state still need to agree.
What you’ll learn
- Distinguish block, file and object interfaces.
- Choose storage from the operations and access pattern.
- Account for durability, requests and transfer costs.
Three interfaces to stored bytes
Block storage presents addressable blocks to a host. A filesystem or database can organize those blocks; attaching a volume does not automatically make it safe for many writers. File storage presents paths, directories and file operations, often shared through NFS or SMB. Locking and filesystem semantics matter.
Object storage presents objects identified by keys, with metadata and an API. It suits media, exports and backups. Do not assume it provides ordinary filesystem rename, append or small in-place writes; the service contract determines available operations.
Measure the actual storage work
A 1 TB dataset is a size, not a speed requirement. Count reads and writes per second, their sizes, sequential versus random access, and acceptable delay. IOPS means input/output operations per second; bytes per second measures transfer volume. Both matter.
Assume 100 photo downloads per second at 2 MB each. That is 200 MB/s before protocol overhead and caching. A CDN can change origin traffic, while thumbnails change payload size. These are exercise numbers, not a storage-product benchmark.
Match storage to the application
Try the design choices
Compare the visible consequences. With JavaScript enabled, choose an option in each scenario to assemble your decision record.
This is an exploratory design exercise. It does not run infrastructure, measure capacity or replace the lesson’s quiz.
Choose a usable interface, then evaluate durability and operating cost.
Compare practical storage options
Local SSDs, Amazon EBS and Ceph RBD provide block-oriented options. NFS servers, Amazon EFS and CephFS provide file-oriented options. Amazon S3, Google Cloud Storage and Ceph’s object gateway provide object interfaces. Ceph is open-source software you operate; hosted cloud services charge for their service and usage.
Read Ceph’s interface architecture and provider documentation for the deployed version or storage class. Compare latency, operation limits, replication, access controls, recovery and lifecycle rules. Do not equate having replicas with having an independent backup.
Include operation charges, retrieval delays where applicable, inter-region transfer and deletion policy. A multi-part upload may leave incomplete pieces; expire abandoned uploads deliberately. See the photo service for publishing metadata and media safely.
Check your reasoning
Check your reasoning
Bring the decisions together
Select an interface the application can use correctly. Measure operations and bytes, then compare the complete durability and cost contract.
Reaching the recap and completing the quizzes are separate milestones.