illumos: manual page: vmstat.8

VMSTAT(8) Maintenance Commands and Procedures VMSTAT(8)

NAME

vmstat - report virtual memory statistics

SYNOPSIS

vmstat [-ipqsS] [-T u | d] [disks] [interval [count]]

DESCRIPTION

vmstat reports virtual memory statistics regarding kernel thread, virtual
memory, disk, trap, and CPU activity.

On MP (multi-processor) systems, vmstat averages the number of CPUs into
the output. For per-processor statistics, see mpstat(8).

vmstat only supports statistics for certain devices. For more general
system statistics, use sar(1), iostat(8), or sar(8).

Without options, vmstat displays a one-line summary of the virtual memory
activity since the system was booted.

During execution of the kernel status command, the state of the system
can change. If relevant, a state change message is included in the vmstat
output, in one of the following forms:

<<device added: sd0>>
<<device removed: sd0>>
<<processors added: 1, 3>>
<<processors removed: 1, 3>>

See disks(8) for device naming conventions for disks.

OPTIONS

The following options are supported:

-i
Report the number of interrupts per device. count and
interval does not apply to the -i option.

-p
Report paging activity in details. This option will display
the following, respectively:

epi
Executable page-ins.

epo
Executable page-outs.

epf
Executable page-frees.

api
Anonymous page-ins.

apo
Anonymous page-outs.

apf
Anonymous page-frees.

fpi
File system page-ins.

fpo
File system page-outs.

fpf
File system page-frees.

When executed in a zone and if the pools facility is active,
all of the above only report activity on the processors in
the processor set of the zone's pool.

-q
Suppress messages related to state changes.

-s
Display the total number of various system events since
boot. count and interval does not apply to the -s option.

-S
Report on swapping rather than paging activity. This option
will change two fields in vmstat's ``paging'' display:
rather than the ``re'' and ``mf'' fields, vmstat will report
``si'' (swap-ins) and ``so'' (swap-outs).

-T u | d
Specify u for a printed representation of the internal
representation of time. See time(2). Specify d for standard
date format. See date(1).

OPERANDS

The following operands are supported:

count
Specifies the number of times that the statistics are
repeated. count does not apply to the -i and -s options.

disks
Specifies which disks are to be given priority in the output
(only four disks fit on a line). Common disk names are id,
sd, xd, or xy, followed by a number (for example, sd2, xd0,
and so forth).

interval
Specifies the last number of seconds over which vmstat
summarizes activity. This number of seconds repeats forever.
interval does not apply to the -i and -s options.

EXAMPLES

Example 1: Using vmstat

The following command displays a summary of what the system is doing
every five seconds.

example% vmstat 5

kthr memory page disk faults cpu
r b w swap free re mf pi p fr de sr s0 s1 s2 s3 in sy cs us sy id
0 0 0 11456 4120 1 41 19 1 3 0 2 0 4 0 0 48 112 130 4 14 82
0 0 1 10132 4280 0 4 44 0 0 0 0 0 23 0 0 211 230 144 3 35 62
0 0 1 10132 4616 0 0 20 0 0 0 0 0 19 0 0 150 172 146 3 33 64
0 0 1 10132 5292 0 0 9 0 0 0 0 0 21 0 0 165 105 130 1 21 78
1 1 1 10132 5496 0 0 5 0 0 0 0 0 23 0 0 183 92 134 1 20 79
1 0 1 10132 5564 0 0 25 0 0 0 0 0 18 0 0 131 231 116 4 34 62
1 0 1 10124 5412 0 0 37 0 0 0 0 0 22 0 0 166 179 118 1 33 67
1 0 1 10124 5236 0 0 24 0 0 0 0 0 14 0 0 109 243 113 4 56 39
^C

example%

The fields of vmstat's display are

kthr
Report the number of kernel threads in each of the three
following states:

r
the number of kernel threads in run queue

b
the number of blocked kernel threads that are waiting for
resources I/O, paging, and so forth

w
the number of swapped out lightweight processes (LWPs)
that are waiting for processing resources to finish.

memory
Report on usage of virtual and real memory.

swap
available swap space (Kbytes)

free
size of the free list (Kbytes)

page
Report information about page faults and paging activity. The
information on each of the following activities is given in
units per second.

re
page reclaims -- but see the -S option for how this field
is modified.

mf
minor faults -- but see the -S option for how this field
is modified.

pi
kilobytes paged in

po
kilobytes paged out

fr
kilobytes freed

de
anticipated short-term memory shortfall (Kbytes)

sr
pages scanned by clock algorithm

When executed in a zone and if the pools facility is active,
all of the above (except for "de") only report activity on the
processors in the processor set of the zone's pool.

disk
Report the number of disk operations per second. There are
slots for up to four disks, labeled with a single letter and
number. The letter indicates the type of disk (s = SCSI, i =
IPI, and so forth); the number is the logical unit number.

faults
Report the trap/interrupt rates (per second).

in
interrupts

sy
system calls

cs
CPU context switches

When executed in a zone and if the pools facility is active,
all of the above only report activity on the processors in the
processor set of the zone's pool.

cpu
Give a breakdown of percentage usage of CPU time. On MP
systems, this is an average across all processors.

us
user time

sy
system time

id
idle time

When executed in a zone and if the pools facility is active,
all of the above only report activity on the processors in the
processor set of the zone's pool.

ATTRIBUTES

See attributes(7) for descriptions of the following attributes:

+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | See below. |
+--------------------+-----------------+

Invocation is evolving. Human readable output is unstable.

NOTES

The sum of CPU utilization might vary slightly from 100 because of
rounding errors in the production of a percentage figure.

May 6, 2020 VMSTAT(8)