If an active process asks the kernel for more memory than there is immediately available, the kernel will write old memory pages out to swap space. This is known as paging.
To stop paging, make sure that there is enough RAM available to support the size of the processes you want to run.
The Most Active Disk gauge in the Disk Activity panel shows the disk with the highest read/write rates.
The Percentage Busy alarm is triggered when the read/write rate of the most active disk exceeds a specified threshold.
A disk that is more than 20% busy (according to Sun Performance and Tuning by A. Cockroft) should be investigated, and possibly have data on it split up and moved to different disks.
The type of alarm that is activated is determined by the percentage of read/write activity experienced by the disk.
The Swap Space panel on the main Spotlight on Unix window shows the total amount of swap space allocated to the machine you are diagnosing, and the amount of swap space currently in use.
If the total amount of swap space allocated to a Unix host becomes full, the machine may halt all processes, or critical actions may be prevented from occurring. Running out of swap space may indicate a runaway process or an under-configured machine.
The type of alarm that is activated is determined by the percentage of swap space currently in use.
The Swap In Flow represents the number of processes swapped from disk per second.
A machine that is swapping processes to or from disk is usually under-configured for its workload.
The type of alarm that is activated is determined by the number of processes swapped from disk every second.