Vmstat o/p

vmstat - Report virtual memory statistics Summary of overall system usage vmstat reports information about processes, memory, paging, block IO, traps, and cpu activity.
The first report produced gives averages since the last reboot. Addi- tional reports give information on a sampling period of length delay. The process and memory reports are instantaneous in either case.
Example : To see usage averaged over 5-second intervals - but display only 8 lines
# vmstat 5 8
procs memory swap io system cpu r b w swpd free buff cache si so bi bo in cs us sy id 0 0 0 0 207904 5760 20524 0 0 86 30 117 47 1 2 96 0 0 0 0 207904 5776 20524 0 0 0 5 103 12 0 0 100 0 0 0 0 207904 5780 20524 0 0 0 1 108 26 0 0 100 0 0 0 0 207904 5780 20524 0 0 0 1 106 19 0 0 100 0 0 0 0 207904 5792 20524 0 0 0 5 112 33 0 0 100 0 0 0 0 207904 5796 20524 0 0 0 7 108 19 0 0 100 0 0 0 0 207904 5808 20524 0 0 0 4 108 24 0 0 100 0 0 0 0 207904 5808 20524 0 0 0 1 107 22 0 0 100
The Table show 6 categories of information on the first line and furtherdetails of each of the major fields
FIELD DESCRIPTIONS Procs - The number of processes and their types
r: The number of processes waiting for run time. b: The number of processes in uninterruptable sleep,which means they are waiting on a resource w: The number of processes swapped out but otherwise ready to run
Memory - Info about physical memory and swap space
swpd: the amount of virtual memory used (kB). free: the amount of idle [free] physical memory (kB). buff: the amount of memory used as buffers (kB). cache: virtual memory that's cached
Swap - Amount of swapping si: Amount of memory swapped in from disk (kB/s). so: Amount of memory swapped to disk (kB/s).
Note : Higher numbers here indicate too much swapping IO - Info about input and output
bi: Blocks sent to a block device (blocks/s). bo: Blocks received from a block device (blocks/s).
Note : Higher numbers here indicate too much disk activity
System - Information about the system
in: The number of interrupts per second, including the clock. cs: The number of context switches per second. i.e. the number of times the kernel changes which process is running
CPU These are percentages of total CPU time used us: % of time used by User process - user time sy: % of time used by system processes - system time id: % of time the CPU was idle - idle time
All linux blocks are currently 1k, except for CD-ROM blocks which are 2k.
See : /proc/meminfo /proc/stat