In today’s relational Database-as-a-Service providers such as Microsoft SQL Azure, resources of a single database server are shared among workloads from multiple tenants. This multi-tenancy enables cost reduction for the cloud service provider which it can pass on as savings to the tenants. However, resource sharing can adversely affect a tenant’s performance due to resource demands of other tenants’ workloads. Service providers today do not provide any assurances to a tenant in terms of isolating its performance from other co-located tenants.

SQLVM is a mechanism for performance isolation via a promise of reservation of key database server resources, such as CPU, I/O and memory for each tenant. One key challenge is supporting this abstraction within the database server process without statically allocating resources to tenants while scaling to large numbers of tenants. Another challenge is to devise low-overhead metering mechanisms to objectively establish accountability if a resource reservation is not met. SQLVM can be viewed as a building block upon which higher-level performance assurances (e.g., at the workload level) can be designed.