vmstat

vmstat (virtual memory statistics) is a computer system monitoring tool that collects and displays summary information about operating system memory, processes, interrupts, paging and block I/O. Users of vmstat can specify a sampling interval which permits observing system activity in near-real time.

vmstat
Developer(s)AT&T Bell Laboratories
Initial releaseFebruary 1985 (1985-02)
Operating systemUnix and Unix-like
TypeCommand

The vmstat tool is available on most Unix and Unix-like operating systems, such as FreeBSD, Linux or Solaris.

Syntax

The syntax and output of vmstat often differs slightly between different operating systems.

# vmstat 2 6
procs -----------memory---------- ---swap-- -----io---- --system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in    cs us sy id wa
 0  0   2536  21496 185684 1353000    0    0     0    14    1     2  0  0 100  0
 0  0   2536  21496 185684 1353000    0    0     0    28 1030   145  0  0 100  0
 0  0   2536  21496 185684 1353000    0    0     0     0 1026   132  0  0 100  0
 0  0   2536  21520 185684 1353000    0    0     0     0 1033   186  1  0 99  0
 0  0   2536  21520 185684 1353000    0    0     0     0 1024   141  0  0 100  0
 0  0   2536  21584 185684 1353000    0    0     0     0 1025   131  0  0 100  0

In the above example the tool reports every two seconds for six iterations.[1]

We can get the customized or required outputs by using various options with vmstat command.

# vmstat –s
this option is use to get Memory Statistics.
# vmstat –d
this option is use to get Disk Statistics.

See also
  • nmon — a system monitor tool for the AIX and Linux operating systems.
  • iostat
  • top
  • sar

References
  1. http://linuxcommand.org/man_pages/vmstat8.html
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