Glossary
Multi-tenant storage
Multi-tenant storage is a storage system shared by several teams, business units or customers, with each tenant's data, access and resource use kept separate from the others. Tenants share hardware and operations while seeing only their own space. Isolation covers both data and performance, and both need to be in place before the second tenant arrives.
How it relates to multi-tenancy
Multi-tenancy describes the platform architecture as a service provider sees it: layers of identity, namespace, capacity, key and audit isolation across a shared service. Multi-tenant storage is the narrower storage question of where a system draws the boundary between tenants, and what each boundary gives up in efficiency in return for separation.
Degrees of isolation
| Tenant boundary | What tenants share | Separation | Efficiency |
|---|---|---|---|
| Bucket or share within one account | Accounts, policies and capacity | Policy only; one administrative error crosses tenants | Highest |
| Separate account per tenant | Hardware and capacity pool | Own identities, policies and keys | High |
| Separate resource pool per tenant | Management and software | Own drives or servers, so no performance interference | Moderate |
| Dedicated cluster | Operations staff only | Physical separation | Lowest |
Most shared platforms use the second level and move heavy or regulated tenants to the third or fourth. The shared capacity behind tenants is covered under storage pooling.
Performance is the half that gets forgotten
Data isolation stops one tenant reading another's data. Performance isolation stops one tenant starving the rest, the noisy-neighbor problem. A tenant running a large restore after an incident can take most of the disk and network capacity while other tenants' jobs slow or miss their windows. Capacity quotas do not prevent this. Per-tenant limits on request rate and bandwidth do, through storage QoS controls, ideally set from the first tenant.
Metering, audit and offboarding
A shared system needs per-tenant figures for capacity, requests and bandwidth, for internal chargeback or customer billing, and per-tenant access logs that a tenant's auditor can read without seeing anyone else's activity. Offboarding raises the hardest question: proving that a departing tenant's data is gone from shared drives. Encrypting each tenant under its own key gives a provable answer, since destroying the key leaves the data unreadable. Enterprises merging departmental file servers through NAS consolidation face the same questions, with departments as the tenants.