ExaCC I/O Resource Management and Storage Performance Tuning
When multiple VM Clusters share the same Exadata storage cells on ExaCC, storage I/O becomes a shared resource that can interfere between workloads. Oracle’s I/O Resource Manager (IORM) is the mechanism for controlling how storage I/O is distributed across VM Clusters, databases, and consumer groups. Without IORM configuration, a single runaway workload on one VM Cluster can starve others. IORM Architecture on ExaCC IORM operates at two levels: Inter-VM Cluster IORM (configured via OCI): Controls storage I/O allocation between VM Clusters sharing the same physical Exadata infrastructure. Intra-database IORM (configured via DBCA or DBRM): Controls I/O between databases within a single VM Cluster and between consumer groups within a database. Because ExaCC does not give customers cellcli access, inter-VM Cluster IORM is configured through the OCI Console or API — Oracle’s management layer pushes the configuration to the storage cells. ...