Spotlight on Oracle 10.9 - Getting Started Guide

Every chart has a legend (list of symbols) to its right that describes the various series (line graphs) on the chart.
Click an item in the legend to highlight its series (line) in the chart. Click a second time to return the series to its normal appearance.
Move the mouse pointer over an item in the legend to view the current value for that series within the chart.

Chart	Description
Physical	The Physical Memory chart shows the total physical memory (RAM) on the Unix host, and the amount of physical memory that is currently free.
Virtual	The Virtual Memory chart shows the total amount of memory in use on the Unix host. This includes physical memory plus space in the paging files. A steady increase in virtual memory usage can indicate that a process on the system has a memory leak.
Paging	The Paging chart shows the rate at which pages are being swapped in and out of memory. The chart displays three data series: Page In - The rate at which read requests are made to the swap device. Page Out - The rate at which write requests are made to the swap device. Scan rate - The rate at which the memory manager scans for a free page in swap. If this rate is rising, it indicates that system memory is under pressure. A sustained high rate of paging can cause problems with overall system degradation due to disk thrashing and CPU load. Note: Scan rate is not available for Linux.
Cache	The Cache chart shows the percentage of recent file requests (read and write) that are satisfied by the memory cache, and that do not require a request to the paging areas on disk.