vmstat - Report virtual memory statistics

vmstat [-a] [-V] [-n] [delay-seconds [ count]]

information about processes, memory, paging, block IO, traps, and cpu activity.

The first report gives averages since reboot.
Additional reports give information on a sampling period . The process and memory reports are instantaneous .

-n the header is displayed only once .

If no delay is specified, one report is printed with the average values since boot.

-a print active/inactive page stats.

-V version

Procs r: waiting for run time.
b: uninterruptable sleep.
w: swapped out but otherwise runnable.
IO bi: Blocks input to a block device (blocks/s).
bo: output from a block device
Memory   swpd: virtual memory used (kB).
free: idle memory (kB).
buff: memory used as buffers (kB).
System in: interrupts per second, including the clock.
cs: context switches per second.
Swap si: memory swapped in from disk (kB/s)  
so: out
CPU percentages of total CPU time.
us: user
sy: system
id: idle

vmstat
   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 534524  90708  78300 1213912    0    1     0     0    1     0  1  1  0
vmstat 60 3
   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 534696  67020  76172 1177164    0    1     0     0    1     0  1  1  0
 0  0  0 534648  63884  78728 1175752    2    0   533   607  385   558 11  2 87
 0  0  0 534636  70252  77504 1177920    3   36  1156   613  705   546 10  2 89

       vmstat does not require special permissions.
These reports are intended to help identify system bottlenecks.
Linux vmstat does not count itself as a running process.

All linux blocks are currently 1k, except for CD-ROM blocks which are 2k.

FILES /proc/meminfo, /proc/stat, /proc/*/stat,

SEE ALSO ps(1), top(1), free(1) sar(1), sadc(8), sa1(8), sa2(8), iostat(1), mpstat(8)