Object storage is a data storage architecture that manages data as discrete objects — each consisting of the data itself, a variable-length metadata dictionary, and a globally unique identifier. Objects are accessed via HTTP-based APIs (most commonly the S3 API, which has become an industry standard) rather than file system hierarchies or block device interfaces.
Object storage vs. file storage vs. block storage
Block storage presents raw storage blocks to an operating system, which formats them as a file system. Used for databases, VM images, and any workload requiring direct disk access. Low latency, but not shareable across multiple hosts without special configurations.
File storage presents a shared file system accessible over a network protocol (NFS, SMB). Used for shared file access, home directories, and application data that multiple servers need to read and write simultaneously.
Object storage is accessed via HTTP APIs — PUT to store an object, GET to retrieve it, DELETE to remove it. Objects are immutable once written (updates create new versions). Massively scalable (petabytes), highly durable (data is replicated across multiple disks and nodes), and accessible from anywhere with network access.
S3 compatibility and sovereignty
AWS S3 is the origin of the dominant object storage API — so widely adopted that "S3-compatible" has become the default expectation for any object storage system. Open-source S3-compatible object storage (MinIO being the most widely deployed) enables organisations to run S3-API-compatible storage on their own hardware, with full compatibility with applications built for S3.
For Indian regulated entities, self-hosted object storage means that ML training datasets, document stores, backup archives, and unstructured data remain on-premise — compliant with data localisation requirements — while maintaining API compatibility with the entire ecosystem of S3-native tools.