Basic introduction to the system resource monitoring tool collectl in Linux

Collectl is a lightweight performance monitoring tool that monitors information such as CPU, disk, bandwidth, memory, network, NFS, and process.

Monitoring System Resources is a necessary task for system administrators. We often need to monitor system resources to solve system problems. The Linux system also comes with many monitoring tools, such as top, vmstat, iostat, and SAR. It is very important to be familiar with these tools, but these tools are too scattered, sometimes we may need to read more comprehensive data. collectl is such a super tool. I have already introduced the IBM monitoring tool nmon. The nmon monitoring is also very comprehensive and visualized. However, compared with nmon, collectl supports sending data through socket, for the monitoring of many machines, nmon has to open many windows, while collectl only needs to view the data of all machines in one window, so it must be recommended!

Open source Web site: http://collectl.sourceforge.net/

 

Unlike most monitoring tools that eitherfocus on a small set of statistics, format their output in only one way, runeither interatively or as a daemon but not both, collectl tries to do it all. you can choose to monitor any of a broad set of subsystems which
Currentlyinclude buddyinfo, CPU, disk, inodes, InfiniBand, lustre, memory, network, NFS, processes, quadrics, slabs, sockets and TCP.

Unlike most monitoring tools, which focus on statistics of a small amount of data, output data is formatted in one way and run in interactive mode or as a daemon background, however, the two methods are not supported at the same time,CollectlTry to implement all the above functions. You can choose to monitor a subset of all subsystems, includingBuddyinfo,
CPU, disk, inodes, InfiniBand, lustre, memory, network, NFS, processes, quadrics, slabs, sockets and TCPInformation.

The following diagram shows that collectl is much more than a tool that reads data from/proc, writes the results to a file, or on a terminal. Taking a few minutes to study this chart can help you better understand the different methods, and you may use collectl more effectively. As you can see, there is a data that depends on different paths and what needs you choose.

 

Interactive Mode

This is the default and in this mode datais read from/proc and passes throughAnalyze. It is really nothing morethan a function that looks at the change between the current and previusvalues. It then divides by the duration of the interval (unless
You specicify-on) and produces the rate, for those values that are indeed Rate Based. thisfunction is also responsible for formatting/disposing the output. More on thatin a little while.

Interaction Mode

This is the default mode. In this mode/ProcRead and analyze data. There is really no special function, that is, to focus on the changes between the current and previous values. This function is used for formatting./Configuration output.

Record Mode

Data passes from/proc the same wayInteractivemodeBut instead of going throughAnalyzeFunction it written itto a file. By eliminating the calculations and formatting, This Is The mostefficient path the data can take and is why
Collectl it so light-weight whenrun in this way.

Recording mode

Data is collected in the same way as in the interactive mode./ProcDirectory, but this mode writes the results to a file through analysis. By excluding computing and formatting output, this is the most effective way to collect data and whyCollectlIn this way, the runtime is so lightweight.

Playback Mode

Here collectl works exactly ally identicalInteractivemodeCould t instead of reading data from/proc it reads it from a file. This means all the switches that control data formatting still apply. There arealso a couple of switches that allow you
To select the time period from whichyou want to play back data.

Playback Mode

This mode is similar to the interactive mode, but the way the software obtains data is not from/ProcFile System, but get data from a file. This means that all options can still be applied. There is also a switch that allows you to view the data playback time period.