查看Linux系统内存、CPU、磁盘使用率和详细信息

一、查看内存占用

1、free

# free -m

以MB为单位显示内存使用情况

[root@localhost ~]# free -m
              total        used        free      shared  buff/cache   available
Mem:          11852        1250        8668         410        1934        9873
Swap:          6015           0        6015

# free -h

以GB为单位显示内存使用情况

[root@localhost ~]# free -h
              total        used        free      shared  buff/cache   available
Mem:            11G        1.2G        8.5G        410M        1.9G        9.6G
Swap:          5.9G          0B        5.9G

# free -t

以总和的形式查询内存的使用信息

[root@localhost ~]# free -t
              total        used        free      shared  buff/cache   available
Mem:       12137332     1285344     8870628      420268     1981360    10105740
Swap:       6160380           0     6160380
Total:     18297712     1285344    15031008

# free -s 5

周期性的查询内存使用信息

每5秒执行一次命令

[root@localhost ~]# free -s 5
              total        used        free      shared  buff/cache   available
Mem:       12137332     1280796     8875008      420268     1981528    10110136
Swap:       6160380           0     6160380

解释：

Mem：内存的使用情况总览表（物理内存）

Swap：虚拟内存。即可以把数据存放在硬盘上的数据

shared：共享内存，即和普通用户共享的物理内存值

buffers：用于存放要输出到disk（块设备）的数据的

cached：存放从disk上读出的数据

total：机器总的物理内存

used：用掉的内存

free：空闲的物理内存

注：物理内存（total）=系统看到的用掉的内存（used）+系统看到空闲的内存（free）

2、查看某个pid的物理内存使用情况

# cat /proc/PID/status | grep VmRSS

[root@localhost ~]# pidof nginx
27327 27326
[root@localhost ~]#
[root@localhost ~]# cat /proc/27327/status | grep VmRSS
VmRSS:      2652 kB
[root@localhost ~]#
[root@localhost ~]# cat /proc/27326/status | grep VmRSS
VmRSS:      1264 kB
[root@localhost ~]#
[root@localhost ~]# pidof java
1973
[root@localhost ~]# cat /proc/1973/status | grep VmRSS
VmRSS:   1166852 kB

由上面可知，nginx服务进程的两个pid所占物理内存为"2652+1264=3916k"

3、查看本机所有进程的内存占比之和

# cat mem_per.sh

[root@localhost ~]# cat mem_per.sh
#!/bin/bash
ps auxw|awk '{if (NR>1){print $4}}' > /opt/mem_list
awk '{MEM_PER+=$1}END{print MEM_PER}'  /opt/mem_list
[root@localhost ~]#
[root@localhost ~]# chmod 755 mem_per.sh
[root@localhost ~]#
[root@localhost ~]# sh mem_per.sh
64.4
[root@localhost ~]# 

脚本配置解释：
ps -auxw|awk '{print $3}'   表示列出本机所有进程的cpu利用率情况，结果中第一行带"%CPU"字符
ps -auxw|awk '{print $4}'   表示列出本机所有进程的内存利用率情况，结果中第一行带"%MEM"字符
ps auxw|awk '{if (NR>1){print $4}}  表示将"ps auxw"结果中的第一行过滤(NR>1)掉，然后打印第4行

二、查看CPU使用情况

1、top

top后键入P看一下谁占用最大

# top -d 5

周期性的查询CPU使用信息

每5秒刷新一次

top - 02:37:55 up 4 min,  1 user,  load average: 0.02, 0.10, 0.05
Tasks: 355 total,   1 running, 354 sleeping,   0 stopped,   0 zombie
%Cpu(s):  3.0 us,  2.8 sy,  0.0 ni, 94.2 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
# us：表示用户空间程序的cpu使用率（没有通过nice调度）
# sy：表示系统空间的cpu使用率，主要是内核程序。
# id：空闲cpu
KiB Mem :  1868660 total,  1081340 free,   578388 used,   208932 buff/cache
KiB Swap:  4194300 total,  4194300 free,        0 used.  1123992 avail Mem 

   PID USER      PR  NI    VIRT    RES    SHR S %CPU %MEM     TIME+ COMMAND                                                                                  
  2220 mysql     20   0 1307796 471172   7608 S  0.6 25.2   0:02.31 mysqld                                                                                   
   349 root      20   0       0      0      0 S  0.4  0.0   0:01.14 kworker/0:3                                                                              
   644 root      20   0       0      0      0 S  0.4  0.0   0:00.17 xfsaild/dm-0                                                                             
  3489 root      20   0  146432   2268   1440 R  0.4  0.1   0:00.11 top                                                                                      
     1 root      20   0   44500   7120   2596 S  0.2  0.4   0:01.69 systemd                                                                                  
   283 root      39  19       0      0      0 S  0.2  0.0   0:00.18 khugepaged                                                                               
  2621 root      20   0  141264   5140   3896 S  0.2  0.3   0:00.18 sshd                                                                                     
     2 root      20   0       0      0      0 S  0.0  0.0   0:00.01 kthreadd                                                                                 
     3 root      20   0       0      0      0 S  0.0  0.0   0:00.01 ksoftirqd/0                                                                              
     4 root      20   0       0      0      0 S  0.0  0.0   0:00.00 kworker/0:0                                                                              
     5 root       0 -20       0      0      0 S  0.0  0.0   0:00.00 kworker/0:0H                                                                             
     6 root      20   0       0      0      0 S  0.0  0.0   0:00.02 kworker/u256:0                                                                           
     7 root      rt   0       0      0      0 S  0.0  0.0   0:00.00 migration/0                                                                              
     8 root      20   0       0      0      0 S  0.0  0.0   0:00.00 rcu_bh                                                                                   
     9 root      20   0       0      0      0 S  0.0  0.0   0:00.00 rcuob/0                                                                                  
    10 root      20   0       0      0      0 S  0.0  0.0   0:00.00 rcuob/1                                                                                  
    11 root      20   0       0      0      0 S  0.0  0.0   0:00.00 rcuob/2                                                                                  

2、ps auxw（查看本机的进程所占cpu和mem的百分比情况）

使用"ps auxw" 可以查看到本机的进程所占cpu和mem的百分比情况

# ps auxw | head -1

%CPU 进程的cpu占用率
%MEM 进程的内存占用率

[root@localhost ~]# ps auxw | head -1
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
[root@localhost ~]#

查看java进程所占本机的cpu百分比， 如下为0.2%

# ps auxw |grep -v grep|grep -w java|awk '{print $3}'

[root@localhost ~]# ps auxw |grep -v grep|grep -w java|awk '{print $3}'
0.2

查看java进程所占本机的内存百分比， 如下为30.0%

# ps auxw |grep -v grep|grep -w java|awk '{print $4}'

[root@localhost ~]# ps auxw |grep -v grep|grep -w java|awk '{print $4}'
30.0

3、查看本机所有进程的CPU占比之和

# cat cpu_per.sh

[root@localhost ~]# cat cpu_per.sh
#!/bin/bash
ps auxw|awk '{if (NR>1){print $3}}' > /opt/cpu_list
awk '{CPU_PER+=$1}END{print CPU_PER}'  /opt/cpu_list
[root@localhost ~]#
[root@localhost ~]# chmod 755 cpu_per.sh
[root@localhost ~]#
[root@localhost ~]# sh cpu_per.sh
44.5
[root@localhost ~]#

三、查看cpu信息（信息记录在/proc/cpuinfo中）

# 总核数 = 物理CPU个数 X 每颗物理CPU的核数

# 总逻辑CPU数 = 物理CPU个数 X 每颗物理CPU的核数 X 超线程数

1、查看虚拟机逻辑CPU的个数

# cat /proc/cpuinfo| grep "processor"| wc -l

[root@localhost ~]# cat /proc/cpuinfo| grep "processor"| wc -l
6

2、查看物理CPU个数

# cat /proc/cpuinfo| grep "physical id"| sort| uniq| wc -l

[root@localhost ~]# cat /proc/cpuinfo| grep "physical id"| sort| uniq| wc -l
1

3、列出CPU详细信息

# lscpu

服务器1：

[root@localhost ~]# lscpu
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                6
On-line CPU(s) list:   0-5
Thread(s) per core:    1
Core(s) per socket:    6
座：                 1
NUMA 节点：         1
厂商 ID：           GenuineIntel
CPU 系列：          6
型号：              15
型号名称：        Intel(R) Core(TM)2 Duo CPU     T7700  @ 2.40GHz
步进：              11
CPU MHz：             2194.916
BogoMIPS：            4389.83
超管理器厂商：  KVM
虚拟化类型：     完全
L1d 缓存：          32K
L1i 缓存：          32K
L2 缓存：           4096K
NUMA 节点0 CPU：    0-5
Flags:                 fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss ht syscall nx lm constant_tsc rep_good nopl eagerfpu pni ssse3 cx16 pcid sse4_2 x2apic hypervisor lahf_lm

服务器2：

[root@bogon ~]# lscpu
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                8
On-line CPU(s) list:   0-7
Thread(s) per core:    1
Core(s) per socket:    8
Socket(s):             1
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 79
Model name:            Intel(R) Xeon(R) CPU E7-4830 v4 @ 2.00GHz
Stepping:              1
CPU MHz:               1995.192
BogoMIPS:              3990.38
Hypervisor vendor:     VMware
Virtualization type:   full
L1d cache:             32K
L1i cache:             32K
L2 cache:              256K
L3 cache:              35840K
NUMA node0 CPU(s):     0-7
Flags:                 fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts mmx fxsr sse sse2 ss ht syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts nopl xtopology tsc_reliable nonstop_tsc aperfmperf eagerfpu pni pclmulqdq ssse3 fma cx16 sse4_1 sse4_2 movbe popcnt aes xsave avx hypervisor lahf_lm 3dnowprefetch epb dtherm arat pln pts

4、查看每个物理CPU中core的个数(即核数)

# cat /proc/cpuinfo| grep "cpu cores"| uniq

[root@localhost ~]# cat /proc/cpuinfo| grep "cpu cores"| uniq
cpu cores       : 6

三、Linux下查看哪些进程占用的CPU和内存资源最多的方法

1、获取占用CPU资源最多的10个进程

 # ps aux | head -1; ps aux | grep -v PID | sort -rn -k +3 | head -10

[root@localhost ~]# ps aux | head -1; ps aux | grep -v PID | sort -rn -k +3 | head -10
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root      9416  0.8  0.0 163544  6284 ?        Ss   08:38   0:00 sshd: root@pts/0
root      3783  0.7  0.0  12072  2032 ?        S    May26 357:27 /bin/bash /usr/local/VMOptimizationTools/sangfor_guest_datareport
root      9545  0.6  0.0 163224  5904 ?        Ss   08:38   0:00 sshd: root@notty
root      3966  0.3  0.0  12704  2676 ?        S    May26 183:12 /bin/bash /usr/local/VMOptimizationTools/sangfor_update_ipc_callback
root      3784  0.3  0.0  12560  2552 ?        S    May26 182:42 /bin/bash /usr/local/VMOptimizationTools/sangfor_sfping
33       10431  0.3  0.1 409704 17832 ?        S    08:38   0:00 /usr/sbin/apache2 -k start
root      3986  0.2  0.0  12452  2280 ?        S    May26 122:23 /bin/bash /usr/local/VMOptimizationTools/sangfor_vm_proxyd_w
root      3781  0.2  0.0  12740  2672 ?        S    May26 115:59 /bin/bash /usr/local/VMOptimizationTools/sangfor_vm_proxyd
500      23785  0.2  2.0 1790172 249528 ?      Ss   Jun25  11:30 oraclehelowin (LOCAL=NO)
root      4053  0.1  0.0  12508  2520 ?        S    May26  75:16 /bin/bash /usr/local/VMOptimizationTools/sangfor_watchdog

2、获取占用内存资源最多的10个进程

# ps aux | head -1; ps aux | grep -v PID | sort -rn -k +4 | head -10

[root@localhost ~]# ps aux | head -1; ps aux | grep -v PID | sort -rn -k +4 | head -10
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
500      32304  0.0  5.7 1794892 700976 ?      Ss   May31   2:53 ora_dbw0_helowin
500       4785  0.0  4.5 1797912 550132 ?      Ss   May29   4:03 ora_dbw0_helowin
500       4796  0.0  3.5 1798308 426468 ?      Ss   May29   2:11 ora_smon_helowin
500      25850  0.0  2.5 1810144 307340 ?      Ss   Jun17   0:10 oraclehelowin (LOCAL=NO)
500      32471  0.0  2.4 1810184 299704 ?      Ss   Jun14   0:30 oraclehelowin (LOCAL=NO)
500       3927  0.0  2.3 1791308 283440 ?      Ss   Jun26   0:13 oraclehelowin (LOCAL=NO)
500       5432  0.0  2.1 1794272 261692 ?      Ss   May29   7:16 ora_cjq0_helowin
500      23785  0.2  2.0 1790172 249528 ?      Ss   Jun25  11:30 oraclehelowin (LOCAL=NO)
500      19092  0.0  2.0 1793248 253080 ?      Ss   Jun21   0:28 oraclehelowin (LOCAL=NO)
500      32310  0.0  1.8 1794224 229200 ?      Ss   May31   1:25 ora_smon_helowin

3、查看占用cpu最高的进程

# ps aux | head -1; ps aux | grep -v PID | sort -rn -k +3 | head -1

[root@localhost ~]# ps aux | head -1; ps aux | grep -v PID | sort -rn -k +3 | head -1
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
root      3783  0.7  0.0  12072  2032 ?        S    May26 357:32 /bin/bash /usr/local/VMOptimizationTools/sangfor_guest_datareport

4、获取占用内存资源最高的进程

# ps aux | head -1; ps aux | grep -v PID | sort -rn -k +4 | head -1

[root@localhost ~]# ps aux | head -1; ps aux | grep -v PID | sort -rn -k +4 | head -1
USER       PID %CPU %MEM    VSZ   RSS TTY      STAT START   TIME COMMAND
500      32304  0.0  5.7 1794892 700976 ?      Ss   May31   2:53 ora_dbw0_helowin

四、Linux下查看某些进程的启动时间和运行时长

比如查看java进程的启动时间和运行时长

# ps -ef|grep -v grep|grep -w java|awk '{print $2}'

# ps -eo pid,lstart,etime | grep 1973

其中：

Mon Jun 24 09:25:41 2019       为java进程的启动时间

4-00:16:55                     为java进程的运行时长，天-小时-分钟-秒

[root@localhost ~]# ps -ef|grep -v grep|grep -w java|awk '{print $2}'
1973
[root@localhost ~]#
[root@localhost ~]# ps -eo pid,lstart,etime | grep 1973
 1973 Mon Jun 24 09:25:41 2019  4-00:16:55
[root@localhost ~]#
[root@localhost ~]# date
Fri Jun 28 09:42:48 CST 2019

查看所有进程的启动事件、运行时长

# ps -eo user,pid,lstart,etime,cmd

查看nginx进程启动的精确时间和启动后运行的时长

# ps -eo pid,lstart,etime,cmd|grep nginx

[root@nginx-proxy-client ~]# ps -eo pid,lstart,etime,cmd|grep nginx
 1418 Mon Jun 24 13:38:18 2019  3-20:21:05 nginx: master process /usr/local/nginx/sbin/nginx
 1419 Mon Jun 24 13:38:18 2019  3-20:21:05 nginx: worker process
 5543 Fri Jun 28 09:59:23 2019       00:00 grep --color=auto nginx
[root@nginx-proxy-client ~]#
[root@nginx-proxy-client ~]# date
2019年 06月 28日 星期五 09:59:45 CST
[root@nginx-proxy-client ~]#

五、查看网络情况

# ifconfig

[root@localhost ~]# ifconfig 
eno16777736: flags=4163  mtu 1500
        inet 192.168.2.80  netmask 255.255.255.0  broadcast 192.168.2.255
        inet6 fe80::20c:29ff:fe4c:ff47  prefixlen 64  scopeid 0x20
        ether 00:0c:29:4c:ff:47  txqueuelen 1000  (Ethernet)
        RX packets 7866  bytes 632606 (617.7 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 215  bytes 31932 (31.1 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

lo: flags=73  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10
        loop  txqueuelen 0  (Local Loopback)
        RX packets 8  bytes 400 (400.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 8  bytes 400 (400.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

# ip a

[root@localhost ~]# ip a
1: lo:  mtu 65536 qdisc noqueue state UNKNOWN 
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eno16777736:  mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:4c:ff:47 brd ff:ff:ff:ff:ff:ff
    inet 192.168.2.80/24 brd 192.168.2.255 scope global eno16777736
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fe4c:ff47/64 scope link 
       valid_lft forever preferred_lft forever

四、查看磁盘以及分区情况

# df -Th

查看分区、挂载情况

[root@localhost ~]# df -Th
Filesystem              Type      Size  Used Avail Use% Mounted on
/dev/mapper/centos-root xfs        15G  2.8G   13G  19% /
devtmpfs                devtmpfs  903M     0  903M   0% /dev
tmpfs                   tmpfs     913M     0  913M   0% /dev/shm
tmpfs                   tmpfs     913M  8.6M  904M   1% /run
tmpfs                   tmpfs     913M     0  913M   0% /sys/fs/cgroup
/dev/sda1               xfs       297M  115M  183M  39% /boot
tmpfs                   tmpfs     183M     0  183M   0% /run/user/0

# lsblk

查看磁盘情况

[root@localhost ~]# lsblk 
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda               8:0    0   20G  0 disk 
├─sda1            8:1    0  300M  0 part /boot
└─sda2            8:2    0   19G  0 part 
  ├─centos-root 253:0    0   15G  0 lvm  /
  └─centos-swap 253:1    0    4G  0 lvm  [SWAP]
sr0              11:0    1    4G  0 rom  

# fdisk -l

查看详细的硬盘分区情况

[root@localhost ~]# fdisk -l

Disk /dev/sda: 21.5 GB, 21474836480 bytes, 41943040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk label type: dos
Disk identifier: 0x0004a0a8

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *        2048      616447      307200   83  Linux
/dev/sda2          616448    40478719    19931136   8e  Linux LVM

Disk /dev/mapper/centos-root: 16.1 GB, 16106127360 bytes, 31457280 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes


Disk /dev/mapper/centos-swap: 4294 MB, 4294967296 bytes, 8388608 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes

end