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This article is about how to monitor the status of Linux servers. The editor thinks it is very practical, so share it with you as a reference and follow the editor to have a look.

We deal with Linux servers every day, especially Linux engineers. In order to ensure the security and performance of the server, we often need to monitor the status of the server to ensure that the work can be carried out smoothly.

1 、 watch

The watch command is used very frequently, and its basic function is to repeat an instruction at a specified frequency. With this command, we can repeatedly call some commands to monitor the server.

By default, the execution period of the watch command is 2 seconds, but we can use the-n option to specify the frequency of running. For example, if we want to execute the date command every 5 seconds, we can do this:

$watch-n 5 date

A server must be used by many people, especially the small partners of the department. For these little friends to fish in troubled waters, we can use some commands to monitor them.

We can who every 10 seconds to see who is using the server.

$watch-n 10 who Every 10.0s: who butterfly: Tue Jan 23 16:02:03 2019 shs: 0 2019-01-23 09:45 (: 0) dory pts/0 2019-01-23 15:50 (192.168.0.5) alvin pts/1 2019-01-23 16:01 (192.168.0.15) shark pts/3 2019-01-23 11:11 (192.168.0.27)

If we find that the system is running slowly, we can call the uptime command to see the average load of the system.

$watch uptime Every 2.0s: uptime butterfly: Tue Jan 23 16:25:48 2019 16:25:48 up 22 days, 4:38, 3 users, load average: 1.15,0.89,1.02

Some key processes must not fail, otherwise it may affect the business, so we can repeat the number of all processes in the server.

$watch-n 5'ps-ef | wc-l 'Every 5.0s: ps-ef | wc-l butterfly: Tue Jan 23 16:11:54 2019 245

To know the server memory usage dynamically, you can repeat the free command.

$watch-n 5 free-m Every 5.0s: free-m butterfly: Tue Jan 23 16:34:09 2019 total used free shared buff/cache available Mem: 5959 776 3276 12 1906 4878 Swap: 2047 0 2047

Of course, not only that, we can also repeatedly call a lot of commands to monitor some key parameters of the server.

2 、 top

Using the top command, we can know many key parameters of the system, and they are updated dynamically. By default, top monitors the overall state of the system, and if we just want to know how someone is using, we can use the-u option to specify that person.

$top-u alvin top-16:14:33 up 2 days, 4:27, 3 users, load average: 0.00,0.01,0.02 Tasks: 199total, 1 running, 198 sleeping, 0 stopped, 0 zombie% Cpu (s): 0.0 us, 0.2 sy, 0.0 ni, 99.8 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st MiB Mem: 5959.4 total, 3277.3 free 776.4 used, 1905.8 buff/cache MiB Swap: 2048.0 total, 2048.0 free, 0.0 used. 4878.4 avail Mem PID USER PR NI VIRT RES SHR S% CPU% MEM TIME+ COMMAND 23026 alvin 200 46340 7820 6504 S 0.0 0.1 systemd 23033 alvin 200 149660 3140 72 S 0.0 0.1 systemd 00.00 (sd-pam) 23125 alvin 20 063396 5100 4092 S 0.0 0.100 00.00 Sshd 23128 alvin 20 0 16836 5636 4284 S 0.0 0.1 0:00.03 zsh

In this result, you can see not only the number of processes running by alvin, but also the system resources (CPU, memory) consumed by each process, while you can still see the key parameters of the entire system.

3 、 ac

If you want to know how long it takes each user to log on to the server, you can use the ac command. This command requires you to install the acct package (Debian) or the psacct package (RHEL,Centos).

If we want to know the sum of the time it takes for all users to log in to the server, we can run the ac command directly without any parameters.

$ac total 1261.72

If we want to know how long each user uses, we can add the-p option.

$ac-p shark 5.24 alvin 5.52 shs 1251.00 total 1261.76

We can also see the sum of the time users spend on the server each day by adding the-d option.

$ac-d | tail-10 Jan 11 total 0.05Jan 12 total 1.36 Jan 13 total 16.39 Jan 15 total 55.33 Jan 16 total 38.02 Jan 17 total 28.51 Jan 19 total 48.66 Jan 20 total 1.37 Jan 22 total 23.48 Today total 9.83 Thank you for reading! This is the end of the article on "how to monitor the status of the Linux server". I hope the above content can be of some help to you, so that you can learn more knowledge. if you think the article is good, you can share it for more people to see!

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