Codex

VMSTAT

Section: System Administration (8)

Updated: September 2011

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NAME

vmstat - Report virtual memory statistics

SYNOPSIS

vmstat [options] [delay [count]]

DESCRIPTION

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

The first report produced gives averages since the last reboot. Additional reports give information on a sampling period of length delay. The process and memory reports are instantaneous in either case.

OPTIONS

delay
The delay between updates in seconds. If no delay is specified, only one report is printed with the average values since boot.:
count
Number of updates. In absence of count, when delay is defined, default is infinite.:
-a, --active
Display active and inactive memory, given a 2.5.41 kernel or better.:
-f, --forks
The -f switch displays the number of forks since boot. This includes the fork, vfork, and clone system calls, and is equivalent to the total number of tasks created. Each process is represented by one or more tasks, depending on thread usage. This display does not repeat.:
-m, --slabs
Displays slabinfo.:
-n, --one-header
Display the header only once rather than periodically.:
-s, --stats
Displays a table of various event counters and memory statistics. This display does not repeat.:
-d, --disk
Report disk statistics (2.5.70 or above required).:
-D, --disk-sum
Report some summary statistics about disk activity.:
-p, --partition device
Detailed statistics about partition (2.5.70 or above required).:
-S, --unit character
Switches outputs between 1000 (k), 1024 (K), 1000000 (m), or 1048576 (M) bytes. Note this does not change the swap (si/so) or block (bi/bo) fields.:
-w, --wide
Wide output mode (useful for systems with higher amount of memory, where the default output mode suffers from unwanted column breakage). The output is wider than 80 characters per line.:
-V, --version
Display version information and exit.:
-h, --help
Display help and exit.:

FIELD DESCRIPTION FOR VM MODE

<H3 CLASS="c2|Procs

<H3 CLASS="c2|Memory

<H3 CLASS="c2|Swap

<H3 CLASS="c2|IO

<H3 CLASS="c2|System

<H3 CLASS="c2|CPU

These are percentages of total CPU time.

FIELD DESCRIPTION FOR DISK MODE

<H3 CLASS="c2|Reads

<H3 CLASS="c2|Writes

<H3 CLASS="c2|IO

FIELD DESCRIPTION FOR DISK PARTITION MODE

FIELD DESCRIPTION FOR SLAB MODE

NOTES

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 1024 bytes. Old kernels may report blocks as 512 bytes, 2048 bytes, or 4096 bytes.

Since procps 3.1.9, vmstat lets you choose units (k, K, m, M). Default is K (1024 bytes) in the default mode.

vmstat uses slabinfo 1.1

FILES

SEE ALSO

free?(1), iostat?(1), mpstat?(1), ps?(1), sar?(1), top?(1)

BUGS

Does not tabulate the block io per device or count the number of system calls.

AUTHORS

Written by Henry Ware

Fabian Frédérick (diskstat, slab, partitions...)

REPORTING BUGS

Please send bug reports to


Index

NAME

SYNOPSIS

DESCRIPTION

OPTIONS

FIELD DESCRIPTION FOR VM MODE

:<A CLASS="c3" HREF="#lbAG|Procs]]

:<A CLASS="c3" HREF="#lbAH|Memory]]

:<A CLASS="c3" HREF="#lbAI|Swap]]

:<A CLASS="c3" HREF="#lbAJ|IO]]

:<A CLASS="c3" HREF="#lbAK|System]]

:<A CLASS="c3" HREF="#lbAL|CPU]]

FIELD DESCRIPTION FOR DISK MODE

:<A CLASS="c3" HREF="#lbAN|Reads]]

:<A CLASS="c3" HREF="#lbAO|Writes]]

:<A CLASS="c3" HREF="#lbAP|IO]]

FIELD DESCRIPTION FOR DISK PARTITION MODE

FIELD DESCRIPTION FOR SLAB MODE

NOTES

FILES

SEE ALSO

BUGS

AUTHORS

REPORTING BUGS