使用vmstat监控系统负载。
环境：
[Oracle@simpleit ~]$ uname -a
Linux simpleit.domain.cn 2.6.18-194.el5 #1 SMP Fri Apr 2 14:58:35 EDT 2010 i686 athlon i386 GNU/Linux
[oracle@simpleit ~]$ cat /etc/RedHat-release
CentOS release 5.5 (Final)
[oracle@simpleit ~]$ vmstat 5 5
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 0 346220 28848 493544 0 0 109 55 1014 155 0 1 98 1 0
0 0 0 346220 28848 493544 0 0 0 21 698 93 0 0 100 0 0
0 0 0 346220 28856 493544 0 0 0 48 703 102 0 0 100 0 0
0 0 0 346220 28856 493544 0 0 0 21 693 94 0 0 100 0 0
0 0 0 346220 28860 493544 0 0 0 30 701 95 0 0 100 0 0
DESCRIPTION
vmstat reports information about processes, memory, paging, block IO, traps, and cpu activ-ity.
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.