The Oracle Service Layer
Besides monitoring the session load on the cluster service and pinpointing issues in load-balancing across cluster instances, this layer monitors the following:
- The availability and responsiveness of the cluster service;
- The number and nature of wait events that occur on each instance of the cluster, and the sessions/session modules affected by these waits;
- The target and estimated MTTR (Mean Time to Recovery) for every instance;
- Accesses to the undo tablespace of an instance.
Figure 1 : The Oracle Service Layer