# 1. What is object storage ? ### Benefits of Object Storage - Scalability: Object storage solutions can handle large amounts of data, making them ideal for growing storage needs. - Global Accessibility: Data stored in object storage can be accessed from any location, facilitating collaboration among distributed teams. - Cost-Effectiveness: Many object storage services offer a pay-as-you-go model, which can be economical for varying storage requirements. ### S3 Horizontal Scaling S3 is truly horizontally scalable — you can store unlimited objects across multiple regions and availability zones without architectural changes. There's no practical upper limit on capacity or concurrent connections. ### NFS/iSCSI Limitations NFS and iSCSI don't scale horizontally in the same way, but the constraint differs: - NFS: A single NFS share (export) is limited by the backend storage system it's mounted from. You can add more NFS shares/exports, but you're adding discrete storage pools, not transparently scaling a single namespace. Multiple NFS shares require application-level awareness of where data lives. - iSCSI: Similar constraint — a single LUN is bounded by its underlying storage. You can add multiple LUNs, but again, you're managing separate storage targets, not seamless horizontal scaling. ### For PBS Remote Backup Context This is relevant: A PBS system backing up to NFS or iSCSI on a traditional SAN can hit capacity limits and requires manual expansion (adding new shares/LUNs). S3 removes this constraint entirely — capacity expands transparently. However, PBS-to-PBS replication over a network still provides better deduplication than S3, even if S3 scales more elegantly. The trade-off is between efficiency (PBS-to-PBS) and unlimited scalability (S3). So you're identifying a real architectural advantage of S3 that shouldn't be overlooked when designing remote backup infrastructure.