Spotlight on Oracle 11.0 - Getting Started Guide

The percentage of time spent in user mode and in privileged mode.

• User mode is a restricted processing mode designed for applications, environment subsystems, and integral subsystems.
• Privileged mode is designed for use by operating system components, and allows direct access to hardware and all memory.

High levels of CPU utilization may trigger the CPU Busy Alarm.

The number of disk transfers per second. Disk IO bottlenecks may trigger the Free Buffer Waits Alarm or Write Complete Wait Alarm.

See also Improve Database Writer Performance and Improve Database I/O.

Note: Spotlight on Oracle does NOT display information in the Disk IO chart if the database is running on Digital Unix.

Paging activity. This includes:

• Pages read into memory per second.
• Pages written out to disk per second.
• Scan rate — the rate at which the operating system scans memory pages for candidates that can be written to disk.

The length of the Processor queue where processes are waiting to be executed. Processes in this queue will run when the CPU becomes available.

A long queue may indicate that the machine you are diagnosing is under-configured for its workload. You may need to check which OS processes are consuming CPU resources. OS Processes Page

The total rate of data traffic across all network interfaces, measured in packets/second. Separate graphs on the chart indicate the rates at which data packets are being:

• Received by the host machine from the network (Packets In).
• Transmitted by the host machine to the network (Packets Out).