Object Storage Fundamentals
Object storage stores data as discrete objects, each with a unique identifier, the data itself, and metadata. Objects are stored in flat namespaces called buckets — there is no directory hierarchy. Objects are accessed via HTTP-based APIs (S3, Swift) rather than file system protocols (NFS, SMB).
Key characteristics: virtually unlimited scalability (petabytes to exabytes), built-in redundancy (erasure coding or replication), rich metadata, and low cost per GB. Object storage is optimized for write-once, read-many access patterns — not for frequent updates or low-latency access.
S3 API Standard
Amazon S3 (Simple Storage Service) API has become the de facto standard for object storage. All major object storage platforms — on-premises and cloud — support the S3 API. This enables applications to work with any S3-compatible storage without code changes.
Key S3 operations: PUT (upload object), GET (download object), DELETE (remove object), LIST (enumerate objects in bucket), and multipart upload (for large objects). S3 also supports: versioning, lifecycle policies, access control lists, and server-side encryption.
On-Premises Object Storage
- MinIO: Open-source, high-performance S3-compatible object storage. Runs on commodity hardware. Delivers very high throughput (100+ GB/s). Popular for AI and analytics workloads. Available as open source or enterprise edition.
- Ceph RADOS Gateway: Open-source distributed storage with S3-compatible interface. Part of the broader Ceph storage platform. Highly scalable; complex to manage.
- NetApp StorageGRID: Enterprise object storage with advanced data management. Strong compliance and governance features. Common in regulated industries.
- Dell ECS: Enterprise object storage platform. Strong multi-site replication. Common in large enterprises.
AI Dataset Management
Object storage is the standard repository for AI training datasets. Key capabilities for AI: S3-compatible API (supported by all ML frameworks), versioning (track dataset versions), metadata (document dataset provenance), and lifecycle policies (automatically archive old datasets).
Typical AI storage workflow: raw data ingested to object storage → preprocessing pipeline reads from object storage, writes processed data back → training job stages data from object storage to parallel file system → training completes, model artifacts written to object storage.
Backup and Archive
Object storage is increasingly used as a backup target, replacing tape for many use cases. Advantages: random access (faster restore than tape), S3 API compatibility (supported by all major backup software), and low cost per GB. Immutable object storage (WORM — Write Once Read Many) provides ransomware-resistant backup.
Object lifecycle policies automatically transition objects to lower-cost storage tiers as they age: standard → infrequent access → archive. This automates cost optimization without manual data management.
Data Protection
Object storage provides built-in data protection through two mechanisms:
- Replication: Multiple copies of each object stored on different nodes. Simple to understand; less storage-efficient (3x replication = 3x storage cost).
- Erasure coding: Data split into fragments with parity fragments. Can tolerate multiple node failures with less storage overhead than replication. Example: 8+4 erasure coding stores 8 data fragments + 4 parity fragments = 1.5x storage overhead vs. 3x for replication.
Selecting Object Storage
Key selection criteria: S3 API compatibility, throughput (GB/s for AI workloads), scalability (petabyte-scale for large deployments), data protection (erasure coding vs. replication), and total cost of ownership. For AI workloads, throughput is the primary criterion — MinIO and WEKA provide the highest throughput. For backup and archive, cost per GB and immutability are primary criteria.