Set up threshold-based alarms for Oracle database instances, pluggable databases, and tablespaces so Cloudmon notifies your team or triggers automated remediation when a metric breaches its defined limit.
Oracle monitoring in Cloudmon covers the full database hierarchy: the CDB (Container Database) instance at the top level, individual PDBs (Pluggable Databases) within a CDB, and tablespaces within each PDB. Alarm rules can be configured at each level independently, allowing you to set instance-wide thresholds on the CDB and more granular thresholds on individual PDBs or tablespaces that have specific capacity or performance requirements.
There are two ways to configure alarm rules for Oracle databases:
Each alarm is built around a simple IF/THEN model, where you select a metric, set a threshold, and define what happens when it is breached. Learn more.
Below are recommended alarm configurations for the most common Oracle database monitoring scenarios:
| Use Case | Entity Level | Metric | Suggested Threshold | Why |
| Tablespace nearing capacity | Tablespace | Tablespace Utilisation | Above 85% for 1 interval | A full tablespace causes ORA-01653 errors and transaction failures. Early warning at 85% gives DBAs time to extend the datafile or add space before applications are impacted. |
| Session limit approaching | CDB Instance | Active Sessions | Above 90% of max sessions for 2 intervals | When Oracle reaches its session limit, new connection attempts fail with ORA-00018. Catching this early identifies connection leaks or abnormal application load before the database becomes unavailable. |
| SGA memory pressure | CDB Instance | SGA Utilisation | Above 90% for 2 intervals | An undersized SGA forces Oracle to read data from disk rather than the buffer cache, causing dramatic query slowdowns that impact all connected applications simultaneously. |
| PGA memory overrun | CDB Instance | PGA Utilisation | Above 85% for 2 intervals | Excessive PGA usage from large sorts or hash joins causes Oracle to spill operations to disk, significantly degrading the performance of complex queries and batch processes. |
| High CPU usage on instance | CDB Instance | CPU Utilisation | Above 85% for 3 intervals | Sustained high CPU on an Oracle instance indicates runaway queries, missing indexes, or a batch process consuming excessive resources, which degrades response times for all concurrent users. |
| PDB availability dropped | PDB | Availability | Below 100% for 1 interval | A PDB that goes into restricted or mounted state is unavailable to its application. In a multi-tenant environment this can affect one application while others on the same CDB continue running, making it easy to miss without dedicated PDB-level monitoring. |
Once saved, all triggers for an Oracle entity are listed in the Triggers table under the Alarm Rule section in that entity's Settings. Each row shows the trigger title, alarm severity, notification configuration, and whether a script is set to run. Triggers can be edited or deleted at any time using the action icons on the right.
To apply consistent alarm coverage across all Oracle instances without configuring each one individually, save the rule as a reusable template under Settings → Configurations → Alarm Rules and associate it to a group. Separate rules can be created for CDB instances, PDBs, and tablespaces so each level has appropriate thresholds.