查看swap使用情况

静态使用情况

free -m 查看内存、swap使用情况，单位为M，默认为K

[sage.wang@machine /proc/19843]$ free -m
             total       used       free     shared    buffers     cached
Mem:          3830       3700        130          0         42        691
-/+ buffers/cache:       2965        865
Swap:         4095         86       4009

历史使用情况

它能列出系统在各个时间的SWAP使用情况，使用sar命令。-S查看swap，-r查看内存使用情况

[sage.wang@machine ~]$ sar -S
Linux 2.6.32-358.23.2.el6.x86_64 (machine)     08/03/2018     _x86_64_    (4 CPU)

12:00:01 AM kbswpfree kbswpused  %swpused  kbswpcad   %swpcad
12:10:01 AM   4105976     88320      2.11     25788     29.20
12:20:01 AM   4105976     88320      2.11     25788     29.20
12:30:01 AM   4105976     88320      2.11     25788     29.20
12:40:01 AM   4105976     88320      2.11     25788     29.20


[sage.wang@machine ~]$ sar -r
Linux 2.6.32-358.23.2.el6.x86_64 (machine)     08/03/2018     _x86_64_    (4 CPU)

12:00:01 AM kbmemfree kbmemused  %memused kbbuffers  kbcached  kbcommit   %commit
12:10:01 AM    608928   3313760     84.48      5256    322840   3185080     39.24
12:20:01 AM    588864   3333824     84.99      6616    342316   3185072     39.24
12:30:01 AM    571256   3351432     85.44      7928    359152   3185080     39.24
12:40:01 AM    551160   3371528     85.95      9296    375488   3185084     39.24

实时大小

使用vmstat查看实时的数据，可以显示刷新频率，每隔1秒刷新一次：

[sage.wang@machine ~]$ vmstat 1
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  88248 118900  39112 727652    0    0     4     7    0    0  1  0 99  0  0    
 0  0  88248 118892  39112 727684    0    0     0     0  333  406  1  0 99  0  0    
 0  0  88248 118916  39112 727716    0    0     0     0  337  442  1  0 99  0  0    
 0  0  88248 118900  39120 727740    0    0     0    12  458  448  2  0 98  0  0

关注几个值

Memory
      swpd: the amount of virtual memory used.   使用的虚拟内存大小
      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).  磁盘->内存
      so: Amount of memory swapped to disk (/s).  内存->磁盘

如果它们一直是零当然最好不过了，偶尔不为零也没啥，糟糕的是一直不为零。

#!/bin/bash

cd /proc

for pid in [0-9]*; do
    command=$(cat /proc/$pid/cmdline)

    swap=$(
        awk '
            BEGIN  { total = 0 }
            /Swap/ { total += $2 }
            END    { print total }
        ' /proc/$pid/smaps
    )

    if (( $swap > 0 )); then
        if [[ "${head}" != "yes" ]]; then
            echo -e "PID\tSWAP\tCOMMAND"
            head="yes"
        fi

        echo -e "${pid}\t${swap}\t${command}"
    fi
done

sudo权限执行

https://huoding.com/2012/11/08/198

https://my.oschina.net/shyl/blog/477122

查看磁盘io

https://my.oschina.net/shyl/blog/477122