memory

vmstat: system statistics about memory, processes, disks, block IO, CPU, and more

vmstat reports information about memory, paging, processes, disks, block IO, CPU activity, and traps.

Typical usage: diagnosing problems, system performance monitoring, troubleshooting

Installation
Usage
- Options
Examples

Installation

When vmstat is not installed by default, it can be added to the system using the relevant software package.

Package information for vmstat

Operating system	Package name	Installation
AlmaLinux	procps-ng	`dnf install procps-ng`
Arch Linux	procps-ng	`pacman -S procps-ng`
Debian	procps	`apt install procps`
Fedora	procps-ng	`dnf install procps-ng`
openSUSE	procps	`zypper install procps`
Red Hat Enterprise Linux	procps-ng	`dnf install procps-ng`
Rocky Linux	procps-ng	`dnf install procps-ng`
Ubuntu	procps	`apt install procps`

Your Linux distribution using a different package? Share your feedback.

Usage

Available options

Long option	Short option	Description
--active	-a	Active and inactive memory
--forks	-f	Number of forks since boot
--slabs	-m	Slab information
--one-header	-n	Header displayed once
--stats	-s	Event counters and memory statistics
--disk	-d	Disk statistics
--disk-sum	-D	Disk activity summary
--partition device	-p	Statistics about partition
--unit character	-S	Change output unit (k=1000, K=1024, m=1000000, M=1048576)
--timestamp	-t	Include timestamp with each line
--wide	-w	Wide output, useful when output does not fit
--version	-v	Version information
--help	-h	Display help

Missing an option in this overview? Share your feedback.

Columns in vmstat output

The vmstat command shows many details in several columns and also uses a lot of abbreviations. This overview helps to look up what each field does.

Column	Section	Description
active	memory	Amount of active memory when using --active
b	procs	Number of process that are in blocked state as they are waiting for IO to complete (e.g. network / disk)
bi	io	Amount received from a block device (KiB/s)
bo	io	Amount sent to a block device (KiB/s)
buff	memory	Amount of memory used as buffers
cache	memory	Amount of memory used as cache
cs	system	Number of context switches per second
free	memory	Amount of idle memory
gu	cpu	Time spent running KVM guest code (guest time, including guest nice)
id	cpu	Time spent idle
in	system	Number of interrupts per second, including the clock
inact	memory	Amount of inactive memory when using --active
r	procs	Number of runnable processes that are running or waiting for in runqueue
si	swap	Amount of memory swapped in from the disk (per second)
so	swap	Amount of memory swapped to the disk (per second)
swpd	memory	Amount of swap memory used
us	cpu	Time spent running non-kernel code (user time, including nice time)
st	cpu	Time stolen from a virtual machine
sy	cpu	Time spent running kernel code (system time)
wa	cpu	Time spent waiting for IO

Examples using vmstat

Basic usage

Run vmstat and show default output

vmstat

Example output:

# vmstat
procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa st
 1  0      0 1512912  55276 332288    0    0     1     1   11   17  0  0 100  0  0

Run vmstat with 2 second delay, repeat 5 times, then stop

vmstat 2 5

Disk IO

Show disk IO from all available block devices

vmstat --disk

Example output:

# vmstat --disk
disk- ------------reads------------ ------------writes----------- -----IO------
       total merged sectors      ms  total merged sectors      ms    cur    sec
loop0     15      0      42       0      0      0       0       0      0      0
loop1     97      0    4312      11      0      0       0       0      0      0
loop2    137      0    4536      23      0      0       0       0      0      0
loop3     86      0    1396      10      0      0       0       0      0      0
loop4     82      0    1392       7      0      0       0       0      0      0
loop5    792      0   22880      44      0      0       0       0      0      0
loop6    113      0    3052      24      0      0       0       0      0      0
loop7   4717      0  419512     239      0      0       0       0      0     62
nvme0n1 1537360 411987 168028478  437136 96280014 83428385 4183423494 385002672      0 102226
nvme1n1 1043258   1389 134580170  330184 5458709  98614 687186776 10619429      0   3203

Statistics

Show all statistics

vmstat --stats

Example output:

# vmstat --stats
      4009172 K total memory
       970616 K used memory
      1456496 K active memory
       564108 K inactive memory
      1715940 K free memory
       100252 K buffer memory
      1520340 K swap cache
      3353020 K total swap
            0 K used swap
      3353020 K free swap
        14200 non-nice user cpu ticks
          346 nice user cpu ticks
         5848 system cpu ticks
     20380254 idle cpu ticks
         3124 IO-wait cpu ticks
         2648 IRQ cpu ticks
         2085 softirq cpu ticks
          290 stolen cpu ticks
            0 non-nice guest cpu ticks
            0 nice guest cpu ticks
      1422665 K paged in
       234061 K paged out
            0 pages swapped in
            0 pages swapped out
          128 pages alloc in dma
       836782 pages alloc in dma32
            0 pages alloc in high
            0 pages alloc in movable
      3884041 pages alloc in normal
      5159077 pages free
      3513107 interrupts
      4963633 CPU context switches
   1735845729 boot time
        16123 forks

Frequently Asked Questions

What is the vmstat command and its purpose?

The vmstat command reports information about memory, paging, processes, disks, block IO, CPU activity, and traps.

Which package provides the vmstat command?

The command vmstat is provided by the procps or procps-ng package.

Relevant articles using the vmstat command

The following articles include an example on how to use vmstat and might be worth further exploring.

Related and similar commands

Linux has a lot of tools and commands available and sometimes you just need that little other tool. Here is a list of commands that are similar or related to vmstat:

Related and similar commands to vmstat
Command	Category	Summary
basename	files	Strips directory and file name suffix from a given path
dmidecode	hardware	Shows hardware information
lscpu	memory	CPU information, virtualization features, CPU vulnerabilities
numactl	processes	Controls NUMA policy for processes and shared memory
pidstat	monitoring	Monitoring CPU, memory, and disk activity
pmap	processes	Shows memory mapping of process
prtstat	processes	Shows process details for selected process like state, CPU and memory usage
pwdx	processes	Shows current working directory of a process
slabtop	memory	Shows slab usage of kernel
smem	memory	Show memory usage including swap
uname	system information	Shows basic system information

Also 💙 the command-line or terminal? Here is a set of cheat sheets for Linux to get more done from within the shell: