系统管理

uptime - 显示系统的运行时间及负载

有时候我们怀疑系统被人重启过,需要看下系统从啥时候开机的,运行了多少天了?

uptime --help

[root@dp27m1 ~]# uptime
 09:09:42 up 31 days,  5:34,  2 users,  load average: 0.00, 0.01, 0.05
[root@dp27m1 ~]# uptime -s
2020-02-18 03:34:52

free - 查看系统内存信息

free --help
man free

free -h
free -h

[root@dp27m1 ~]# free -h
              total        used        free      shared  buff/cache   available
Mem:            15G        506M         12G         49M        3.0G         14G
Swap:            0B          0B          0B

一般我们看系统的剩余内存,只需要看available的容量即可,每个字段的具体解释可参考man help

# buffer 和 cache 有什么区别 ?
    buffer 缓冲区  cache 缓存,读cache,写buffer
    buffer和cache是内存中的2个不同的区域。
    buffer 把数据写入到内存的buffer区域,写buffer或者叫做,写缓冲
    cache缓存区 从内存中的cache区域进行读取,读cache,读缓存

df - 查看磁盘剩余空间

man df
df --help

[root@dp27m1 ~]# df -hT
Filesystem     Type      Size  Used Avail Use% Mounted on
devtmpfs       devtmpfs  7.9G     0  7.9G   0% /dev
tmpfs          tmpfs     7.9G     0  7.9G   0% /dev/shm
tmpfs          tmpfs     7.9G   50M  7.8G   1% /run
tmpfs          tmpfs     7.9G     0  7.9G   0% /sys/fs/cgroup
/dev/sda2      xfs        30G  1.8G   28G   6% /
/dev/sda1      xfs       497M   64M  433M  13% /boot
/dev/sdb1      ext4       32G   49M   30G   1% /mnt/resource
/dev/sdc       ext4      252G  6.7G  233G   3% /data
tmpfs          tmpfs     1.6G     0  1.6G   0% /run/user/1000

vmstat - 虚拟内存统计

vmstat --help

[root@dp27m1 ~]# vmstat -d -w
disk- -------------------reads------------------- -------------------writes------------------ ------IO-------
          total    merged     sectors          ms     total    merged     sectors          ms     cur     sec
fd0           0         0           0           0         0         0           0           0       0       0
sdb         469         0       33242         582      1397     33630    68427144      287924       0       2
sr0          39         0         248          43         0         0           0           0       0       0
sdc     1319553     22040   147411378   167502122 194337422 133816139  4362182776  1570284439       0  615174
sda      462686       358    75929054    65008658   3218992     23000    36004558     9527545       0    1856
[root@dp27m1 ~]# vmstat -w

procs -----------------------memory---------------------- ---swap-- -----io---- -system-- --------cpu--------
 r  b         swpd         free         buff        cache   si   so    bi    bo   in   cs  us  sy  id  wa  st
 1  0            0     12757292       194064      2942496    0    0    11   185    4    4   6   5  84   5   0

上面字段的详细含义可参考 man vmstat

mpstat - CPU信息统计

[root@dp27m1 ~]# mpstat
Linux 3.10.0-1062.9.1.el7.x86_64 (dp27m1) 	03/20/2020 	_x86_64_	(4 CPU)

09:50:14 AM  CPU    %usr   %nice    %sys %iowait    %irq   %soft  %steal  %guest  %gnice   %idle
09:50:14 AM  all    6.04    0.00    3.86    5.02    0.00    1.21    0.00    0.00    0.00   83.87

iostat - I/O信息统计

[root@dp27m1 ~]# iostat
Linux 3.10.0-1062.9.1.el7.x86_64 (dp27m1) 	03/20/2020 	_x86_64_	(4 CPU)

avg-cpu:  %user   %nice %system %iowait  %steal   %idle
           6.04    0.00    5.07    5.02    0.00   83.87

Device:            tps    kB_read/s    kB_wrtn/s    kB_read    kB_wrtn
sdb               0.00         0.01        12.67      16637   34213632
scd0              0.00         0.00         0.00        124          0
sdc              72.44        27.29       807.50   73705689 2181091388
sda               1.36        14.06         6.67   37964743   18005693

iotop - 动态显示磁盘I/O统计信息

yum install iotop
iostat -k

这个工具用来快速显示磁盘读写速度还是挺方便的

sar - 收集系统历史负载

sar -h
sar --help

https://abdussamad.com/archives/167-CPU-load-average-history-in-Linux.html

sar -q
/var/log/sa 

ls -lrht --full-time /var/log/sa
sar -q -s 22:00:00 -e 00:00:00 -f /var/log/sa/sa10


2020-03-19 22:00~00:00 历史负载情况 
[root@xingyongsheng sa]# sar -q -s 22:00:00 -e 00:00:00 -f /var/log/sa/sa19
Linux 3.10.0-957.1.3.el7.x86_64 (xingyongsheng) 	03/19/2020 	_x86_64_	(2 CPU)
10:00:01 PM   runq-sz  plist-sz   ldavg-1   ldavg-5  ldavg-15   blocked
10:10:01 PM         7      1288      0.20      0.27      0.28         0
10:20:01 PM         5      1288      0.12      0.29      0.31         0
10:30:01 PM         4      1288      0.23      0.34      0.33         0
10:40:01 PM         1      1288      0.15      0.19      0.25         0
10:50:01 PM         1      1288      0.31      0.20      0.23         0
11:00:01 PM         4      1288      0.02      0.17      0.22         0
11:10:01 PM         7      1288      0.26      0.43      0.34         0
11:20:01 PM         4      1289      0.31      0.35      0.34         0
11:30:01 PM         2      1288      0.38      0.33      0.32         0
11:40:01 PM         5      1288      0.36      0.32      0.32         0
11:50:01 PM         3      1289      0.38      0.47      0.41         0
Average:            4      1288      0.25      0.31      0.30         0

chkconfig - 管理开机服务

[root@node1 ~]# chkconfig  --list

Note: This output shows SysV services only and does not include native
      systemd services. SysV configuration data might be overridden by native
      systemd configuration.

      If you want to list systemd services use 'systemctl list-unit-files'.
      To see services enabled on particular target use
      'systemctl list-dependencies [target]'.

netconsole     	0:off	1:off	2:off	3:off	4:off	5:off	6:off
network        	0:off	1:off	2:on	3:on	4:on	5:on	6:off

chkconfig --level 3 sshd off
chkconfig --list sshd
chkconfig --level 3 sshd on


ethtool - 查询网卡参数

ethtool eth0

mii-tool - 管理网络接口状态

[root@node1 ~]# mii-tool eth0
eth0: no autonegotiation, 1000baseT-FD flow-control, link ok

dmidecode - 查询系统硬件信息

[root@xingyongsheng ~]# dmidecode -s
dmidecode: option requires an argument -- 's'
String keyword expected
Valid string keywords are:
  bios-vendor
  bios-version
  bios-release-date
  system-manufacturer
  system-product-name
  system-version
  system-serial-number
  system-uuid
  system-family
  baseboard-manufacturer
  baseboard-product-name
  baseboard-version
  baseboard-serial-number
  baseboard-asset-tag
  chassis-manufacturer
  chassis-type
  chassis-version
  chassis-serial-number
  chassis-asset-tag
  processor-family
  processor-manufacturer
  processor-version
  processor-frequency
[root@xingyongsheng ~]# 
[root@xingyongsheng ~]# dmidecode -s system-product-name
Alibaba Cloud ECS
[root@xingyongsheng ~]# dmidecode -s system-version
pc-i440fx-2.1
[root@xingyongsheng ~]# dmidecode -s processor-frequency
Unknown

[root@xingyongsheng ~]# dmidecode -t bios
# dmidecode 3.2
Getting SMBIOS data from sysfs.
SMBIOS 2.8 present.

Handle 0x0000, DMI type 0, 24 bytes
BIOS Information
	Vendor: SeaBIOS
	Version: 8c24b4c
	Release Date: 04/01/2014
	Address: 0xE8000
	Runtime Size: 96 kB
	ROM Size: 64 kB
	Characteristics:
		BIOS characteristics not supported
		Targeted content distribution is supported
	BIOS Revision: 0.0

lspci - 显示所有PCI设备

[root@xingyongsheng ~]# lspci
00:00.0 Host bridge: Intel Corporation 440FX - 82441FX PMC [Natoma] (rev 02)
00:01.0 ISA bridge: Intel Corporation 82371SB PIIX3 ISA [Natoma/Triton II]
00:01.1 IDE interface: Intel Corporation 82371SB PIIX3 IDE [Natoma/Triton II]
00:01.2 USB controller: Intel Corporation 82371SB PIIX3 USB [Natoma/Triton II] (rev 01)
00:01.3 Bridge: Intel Corporation 82371AB/EB/MB PIIX4 ACPI (rev 03)
00:02.0 VGA compatible controller: Cirrus Logic GD 5446
00:03.0 Ethernet controller: Red Hat, Inc. Virtio network device
00:04.0 Communication controller: Red Hat, Inc. Virtio console
00:05.0 SCSI storage controller: Red Hat, Inc. Virtio block device
00:06.0 Unclassified device [00ff]: Red Hat, Inc. Virtio memory balloon

ipcs - 显示进程间通信设施的状态

[root@xingyongsheng ~]# ipcs

------ Message Queues --------
key        msqid      owner      perms      used-bytes   messages    

------ Shared Memory Segments --------
key        shmid      owner      perms      bytes      nattch     status      

------ Semaphore Arrays --------
key        semid      owner      perms      nsems     
0x002fa327 0          root       600        2         

ipcrm - 清楚ipc相关信息

没什么暖用