TranslateProject/sources/Glances – An Advanced Real Time System Monitoring Tool for Linux.md
2014-02-24 13:12:31 +08:00

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Glances An Advanced Real Time System Monitoring Tool for Linux
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Earlier, weve written about many Linux [System Monitor Tools][1] that can be used to monitor performance of Linux systems, but we think that, most users prefer the default one that comes with every Linux distributions (**top** command).
The [top command][2] is real time task manager in Linux and the most frequently used system monitoring tool in **GNU/Linux** distributions to find the performance related bottlenecks in system which help us to take corrective actions. It has a nice minimalist interface, comes with few amount of reasonable options that enables us to get a better idea about overall system performance quickly.
However, sometimes its very tricky to find an application/process that consuming lots of system resources is a bit difficult under top. Because top command doesnt have a ability to highlights programs that are eating too much of **CPU**, **RAM**, other resources.
For keeping such approach, here we are bringing a powerful system monitor program called “**Glances**” that automatically highlights programs that are utilizing highest system resources and providing maximum of information about Linux/Unix server.
### What is Glances? ###
**Glances** is a cross-platform command-line curses-based system monitoring tool written in **Python** language which use the **psutil** library to grab informations from the system. With Glance, we can monitor **CPU, Load Average, Memory, Network Interfaces, Disk I/O, Processes** and **File System** spaces utilization.
Glances is a free tool and licensed under **GPL** to monitory **GNU/Linux** and **FreeBSD** operating systems. There are lots of interesting options available in Glances as well. One of the main features we have seen in Glances is that we can set thresholds (**careful**, **warning** and **critical**) in configuration file and informations will be shown in colors which indicates the bottleneck in the system.
### Glances Features ###
- CPU Informations (user related applications, system core programs and idle programs.
- Total memory Information including RAM, Swap, Free memory etc.
- The average CPU load for the past 1min, 5mins and 15 mins.
- Network Download/Upload rates of network connections.
- Total number of processes, active ones, sleeping processes etc.
- Disk I/O related (read or write) speed details
- Currently mounted devices disk usages.
- Top processes with their CPU/Memory usages, Names and location of application.
- Shows the current date and time at bottom.
- Highlights processes in Red that consumes highest system resources.
Here is an example screen grab of Glances.
![Glances View](http://www.tecmint.com/wp-content/uploads/2014/02/Glances-Monitoring.jpeg)
### Installation of Glances in Linux/Unix Systems ###
Although its a very young utility, you can install “**Glances**” in **Red Hat** based systems by turning on [EPEL repository][3] and then run the following command on the terminal.
#### On RHEL/CentOS/Fedora ####
# yum install -y glances
#### On Debian/Ubuntu/Linux Mint ####
$ sudo apt-add-repository ppa:arnaud-hartmann/glances-stable
$ sudo apt-get update
$ sudo apt-get install glances
### Usage of Glances ###
To start, issue the basic syntax on the terminal.
# glances
![Glances Preview Ubuntu 13.10](http://www.tecmint.com/wp-content/uploads/2014/02/Glances-Screen.jpeg)
Press **q** or (**ESC** or **Ctrl&C** also works) to quit from Glances terminal. Here, is the another screen grab taken from the **CentOS 6.5** system.
![Glances Preview CentOS 6.5](http://www.tecmint.com/wp-content/uploads/2014/02/Glances-Screen-Centos.jpeg)
y default, interval time is set to **1** second. But you can define the custom interval time while running glances from the terminal.
# glances -t 2
### Glances Color Codes ###
Meaning of Glances color code:
- GREEN: OK (everything is fine)
- BLUE: CAREFUL (need attention)
- VIOLET: WARNING (alert)
- RED: CRITICAL (critical)
We can set thresholds in configuration file. By default thresholds set is (**careful=50, warning=7**0 and **critical=90**), we can customized as per our needs. The default configuration file is located at **/etc/glances/glances.conf**.
### Glances Options ###
Besides, several command line options, glances provides many more **hot keys** to find output information while glances is running. Below are the list of several hot keys.
- a Sort processes automatically
- c Sort processes by CPU%
- m Sort processes by MEM%
- p Sort processes by name
- i Sort processes by I/O rate
- d Show/hide disk I/O stats ols
- f Show/hide file system statshddtemp
- n Show/hide network stats
- s Show/hide sensors stats
- y Show/hide hddtemp stats
- l Show/hide logs
- b Bytes or bits for network I/Oools
- w Delete warning logs
- x Delete warning and critical logs
- x Delete warning and critical logs
- 1 Global CPU or per-CPU stats
- h Show/hide this help screen
- t View network I/O as combination
- u View cumulative network I/O
- q Quit (Esc and Ctrl-C also work)
### Use Glances on Remote Systems ###
With the Glances, you can even monitor remote systems too. To use **glances** on remote systems, run the **glances -s** (-s enables server/client mode) command on the server.
# glances -s
Define the password for the Glances server
Password:
Password (confirm):
Glances server is running on 0.0.0.0:61209
**Note** : Once, you issue **glances** command, it will prompt you to define the password for the Glances server. Define the password and hit enter, you see glances running on port **61209**.
Now, go to the remote host and execute the following command to connect to a Glances server by specifying IP address or hostname as shown below. Here **172.16.27.56** is my glances server IP Address.
# glances -c -P 172.16.27.56
Below are few notable points that user must know while using glances in server/client mode.
* In server mode, you can set the bind address -B ADDRESS and listening TCP port -p PORT.
* In client mode, you can set the TCP port of the server -p PORT.
* Default binding address is 0.0.0.0, but it listens on all network interfaces at port 61209.
* In server/client mode, limits are set by the server side.
* You can also define a password to access to the server -P password.
### Conclusion ###
**Glances** is a much resources friendly tool for most users. But if youre a system administrator whod like to quickly get overall “idea” about systems by just glancing at command line, then this tool will be must have tool for system administrators.
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via: http://www.tecmint.com/glances-an-advanced-real-time-system-monitoring-tool-for-linux/
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[1]:http://www.tecmint.com/command-line-tools-to-monitor-linux-performance/
[2]:http://www.tecmint.com/12-top-command-examples-in-linux/
[3]:http://www.tecmint.com/how-to-enable-epel-repository-for-rhel-centos-6-5/