Monitor Oracle database instances in real time. Track availability, session activity, memory usage, query performance, tablespace health, and more from a single view.
Cloudmon provides deep monitoring for Oracle Database instances running on both Windows and Linux. The Cloudmon agent can be installed directly on the Oracle database server or on a remote machine with network access to the database. Once an instance is added, all Pluggable Databases (PDBs) and their associated Tablespaces are automatically discovered, and detailed metrics are collected at the instance, PDB, and Tablespace level.
Navigate to Servers → Oracle Instance to view all monitored Oracle instances.
Before registering an Oracle instance, a dedicated monitoring user must be created in the database with the permissions required for Cloudmon to collect metrics. Run the following on the Oracle server:
Replace username and password with your chosen values. The Cloudmon agent can be installed on the Oracle server itself or on a separate remote host with connectivity to the Oracle listener. If using a remote agent, ensure the Oracle listener is accepting remote connections and that the firewall allows traffic on the Oracle port, which defaults to 1521.
Cloudmon tracks availability percentage, active session count, uptime, query execution health, and disk I/O in real time. These indicators give teams an immediate read on whether the database is healthy and operating under normal load, without needing to log into the server directly.
Cloudmon monitors both the System Global Area (SGA) and Program Global Area (PGA) in detail. For the SGA, it tracks Buffer Cache Size, Shared Pool Size, Redo Buffers, Physical Reads Per Second, etc. For the PGA, it tracks Total PGA In Use, Cache Hit Percentage, Over Allocation Count, Maximum PGA Allocated, etc.
Oracle's memory architecture is one of the most impactful tuning surfaces in the database. An undersized Buffer Cache drives unnecessary disk reads. A Shared Pool that is too small forces Oracle to repeatedly parse SQL instead of reusing cached execution plans. High PGA Over Allocation means sort and hash join operations are spilling to disk, degrading analytical and batch workloads significantly. Monitoring both SGA and PGA together gives DBAs the visibility needed to tune memory allocation before performance issues reach end users.
Cloudmon discovers and monitors all tablespaces within the instance, tracking their status, allocation method, extent management type, and space utilisation. A full tablespace in Oracle will immediately block any new writes to it, causing application errors or transaction failures with no warning to end users. Proactive tablespace monitoring allows teams to add datafiles or enable autoextend before capacity becomes a critical incident.
In Oracle's multitenant architecture, each Pluggable Database is an isolated database sharing the underlying Container Database infrastructure. Cloudmon automatically discovers and lists all PDBs within an instance. This gives teams visibility into which pluggable database is consuming resources or experiencing issues, without losing sight of the others running on the same instance.
Cloudmon supports threshold-based alarms on any Oracle metric collected at the instance, PDB, or tablespace level, including session count, tablespace utilisation, PGA over allocation, buffer cache hit ratio, and disk I/O. 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.
| Symptom | Likely Cause | Fix |
| Instance not appearing in the list | The instance has not been registered, or the agent cannot connect to the database | Re-run the registration command and verify the hostname, port, service name, and credentials |
| High Hard Parse Per Second | Applications are not using bind variables, forcing Oracle to parse each SQL statement as unique | Review application SQL and enforce use of bind variables to reduce parse overhead and latch contention |
| Low Buffer Cache Hit Ratio | The SGA Buffer Cache is undersized for the current workload | Review SGA metrics and increase the Buffer Cache Size in the Oracle memory configuration |
| Tablespace running out of space | Data growth has consumed most of the tablespace allocation | Add a datafile to the tablespace or enable autoextend to prevent write failures |
| High PGA Over Allocation Count | The PGA target is too small, causing sort operations to spill to disk | Increase PGA_AGGREGATE_TARGET in the Oracle configuration |