用途
查看系统资源整体使用情况，包括进程数量，CPU，内存，IO，swap等资源统计信息
用法
vmstat [options] [delay [ count]]
常用选项
-a
显示active/inactive内存
-f
显示forks的数量
-t
显示时间
-m
显示slab信息
-n
信息头部只输出一次，默认会周期性的输出
-s
表格形式显示事件计数器和内存的统计信息
-d
报告硬盘统计信息
-w
增加字段的宽度，显示更加易于查看
-p partition name
显示指定分区的统计信息
-S
内存显示单位(The -S followed by k or K or m or M switches outputs between 1000, 1024, 1000000, or 1048576 bytes)
-V
显示程序版本信息
实践
1 每个2秒报告一次系统情况
[root@vm ~]# vmstat 2
procs -----------memory---------- ---swap-- -----io---- --system-- -----cpu-----
r b swpd free buff cache si so bi bo in cs us sy id wa st
0 0 1022280 189004 13016 177984 8 21 46 107 313 419 2 1 96 1 0
1 0 1022280 188740 13024 178004 0 0 10 76 525 611 1 0 98 1 0
0 0 1022280 188856 13032 177996 0 0 10 12 367 402 0 1 98 1 0
0 0 1022280 188716 13032 178024 0 0 0 0 465 428 0 0 99 0 0
......
2 显示硬盘统计信息
[root@vm ~]# vmstat -d
disk- ------------reads------------ ------------writes----------- -----IO------
total merged sectors ms total merged sectors ms cur sec
ram0 0 0 0 0 0 0 0 0 0 0
ram1 0 0 0 0 0 0 0 0 0 0
ram2 0 0 0 0 0 0 0 0 0 0
ram3 0 0 0 0 0 0 0 0 0 0
ram4 0 0 0 0 0 0 0 0 0 0
ram5 0 0 0 0 0 0 0 0 0 0
ram6 0 0 0 0 0 0 0 0 0 0
ram7 0 0 0 0 0 0 0 0 0 0
ram8 0 0 0 0 0 0 0 0 0 0
ram9 0 0 0 0 0 0 0 0 0 0
ram10 0 0 0 0 0 0 0 0 0 0
ram11 0 0 0 0 0 0 0 0 0 0
ram12 0 0 0 0 0 0 0 0 0 0
ram13 0 0 0 0 0 0 0 0 0 0
ram14 0 0 0 0 0 0 0 0 0 0
ram15 0 0 0 0 0 0 0 0 0 0
loop0 0 0 0 0 0 0 0 0 0 0
loop1 0 0 0 0 0 0 0 0 0 0
loop2 0 0 0 0 0 0 0 0 0 0
loop3 0 0 0 0 0 0 0 0 0 0
loop4 0 0 0 0 0 0 0 0 0 0
loop5 0 0 0 0 0 0 0 0 0 0
loop6 0 0 0 0 0 0 0 0 0 0
loop7 0 0 0 0 0 0 0 0 0 0
sda 167694 114908 4595756 1453122 146213 1199662 10667146 3261091 0 583
disk- ------------reads------------ ------------writes----------- -----IO------
total merged sectors ms total merged sectors ms cur sec
dm-0 179304 0 3766554 1811878 1068455 0 8528160 18130295 0 542
dm-1 102612 0 820896 428945 267367 0 2138936 207822027 0 77
3 表格形式显示内存统计信息
[root@vm ~]# vmstat -s
3088360 total memory
2889484 used memory
2100284 active memory
629288 inactive memory
198876 free memory
10792 buffer memory
170184 swap cache
1675260 total swap
1028168 used swap
647092 free swap
124475 non-nice user cpu ticks
21 nice user cpu ticks
26541 system cpu ticks
4815453 idle cpu ticks
57706 IO-wait cpu ticks
5211 IRQ cpu ticks
1100 softirq cpu ticks
0 stolen cpu ticks
2300650 pages paged in
5367081 pages paged out
102312 pages swapped in
267367 pages swapped out
15726774 interrupts
21089251 CPU context switches
1521510912 boot time
76080 forks
输出字段说明
懒得翻译了，这里直接做个备份，日后查看使用
FIELD DESCRIPTION FOR VM MODE
Procs
r: The number of processes waiting for run time.
b: The number of processes in uninterruptible sleep.
Memory
swpd: the amount of virtual memory used.
free: the amount of idle memory.
buff: the amount of memory used as buffers.
cache: the amount of memory used as cache.
inact: the amount of inactive memory. (-a option)
active: the amount of active memory. (-a option)
Swap
si: Amount of memory swapped in from disk (/s).
so: Amount of memory swapped to disk (/s).
IO
bi: Blocks received from a block device (blocks/s).
bo: Blocks sent to a block device (blocks/s).
System
in: The number of interrupts per second, including the clock.
cs: The number of context switches per second.
CPU
These are percentages of total CPU time.
us: Time spent running non-kernel code. (user time, including nice time)
sy: Time spent running kernel code. (system time)
id: Time spent idle. Prior to Linux 2.5.41, this includes IO-wait time.
wa: Time spent waiting for IO. Prior to Linux 2.5.41, included in idle.
st: Time stolen from a virtual machine. Prior to Linux 2.6.11, unknown.
FIELD DESCRIPTION FOR DISK MODE
Reads
total: Total reads completed successfully
merged: grouped reads (resulting in one I/O)
sectors: Sectors read successfully
ms: milliseconds spent reading
Writes
total: Total writes completed successfully
merged: grouped writes (resulting in one I/O)
sectors: Sectors written successfully
ms: milliseconds spent writing
IO
cur: I/O in progress
s: seconds spent for I/O
FIELD DESCRIPTION FOR DISK PARTITION MODE
reads: Total number of reads issued to this partition
read sectors: Total read sectors for partition
writes : Total number of writes issued to this partition
requested writes: Total number of write requests made for partition
FIELD DESCRIPTION FOR SLAB MODE
cache: Cache name
num: Number of currently active objects
total: Total number of available objects
size: Size of each object
pages: Number of pages with at least one active object
totpages: Total number of allocated pages
pslab: Number of pages per slab
参考资料
【1】man vmstat
【2】Linux vmstat命令实战详解
http://www.cnblogs.com/ggjucheng/archive/2012/01/05/2312625.html
【3】vmstat命令
http://man.linuxde.net/vmstat
【4】Linux inactive memory
https://unix.stackexchange.com/questions/305606/linux-inactive-memory
【5】What is active memory and inactive memory?
https://stackoverflow.com/questions/18529723/what-is-active-memory-and-inactive-memory