| Tutorial details | |
|---|---|
| Difficulty | Intermediate (rss) |
| Root privileges | Yes |
| Requirements | RHEL / SL / CentOS Fedora Linux |
vnstat command is a console-based network traffic monitor. It keeps a log of hourly, daily and monthly network traffic for the selected interface(s). However, it isn't a packet sniffer. The traffic information is analyzed from the proc filesystem. That way vnStat can be used even without root permissions.
Installation
First, turn on EPEL repo. Type the the following yum command to install vnstat:
# yum install vnstat
Loaded plugins: auto-update-debuginfo, product-id, protectbase, rhnplugin,
: subscription-manager
Updating certificate-based repositories.
Unable to read consumer identity
0 packages excluded due to repository protections
Setting up Install Process
Resolving Dependencies
--> Running transaction check
---> Package vnstat.x86_64 0:1.11-1.el6 will be installed
--> Finished Dependency Resolution
Dependencies Resolved
================================================================================
Package Arch Version Repository Size
================================================================================
Installing:
vnstat x86_64 1.11-1.el6 epel 102 k
Transaction Summary
================================================================================
Install 1 Package(s)
Total download size: 102 k
Installed size: 283 k
Is this ok [y/N]: y
Downloading Packages:
vnstat-1.11-1.el6.x86_64.rpm | 102 kB 00:00
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
Installing : vnstat-1.11-1.el6.x86_64 1/1
Installed products updated.
Verifying : vnstat-1.11-1.el6.x86_64 1/1
Installed:
vnstat.x86_64 0:1.11-1.el6
Complete!
Configuration
Edit /etc/sysconfig/vnstat, enter:
# vi /etc/sysconfig/vnstat
Sample outputs:
VNSTAT_OPTIONS="-u -i eth0"
Edit /etc/vnstat.conf, enter:
# vi /etc/vnstat.conf
Set default interface to eth1:
Interface "eth1"
The file is self documented so set the options as per your local setup. Save and close the file.
Create the database
You need to run the following command to create the database. But, first set vnstat shell to /bin/bash using the chsh commad
# chsh -s /bin/bash vnstat
# grep --color vnstat /etc/passwd
# id vnstat
This is usually the first command used after a fresh install. Use the runuser command to create the database for eth0 interface:
# runuser -l vnstat -g vnstat -c '/usr/bin/vnstat -u -i eth0'
To create the database for eth1 interface, run:
# runuser -l vnstat -g vnstat -c '/usr/bin/vnstat -u -i eth1'
Make sure vnstat user can not login i.e. refuse a login for vnstat user:
# chsh -s /sbin/nologin vnstat
# grep --color vnstat /etc/passwd
# id vnstat
Start vnstat service
Type the following chkconfig command to turn on vnstat service at boot time:
# chkconfig vnstat on
To start / stop / restart and control vnstart service, run:
# service vnstat start
# service vnstat stop
# service vnstat restart
# service vnstat status
How do I view stats?
The syntax is:
vnstat vnstat -i {interface} vnstat -i {interface} -option vnstat -i {interface} -option1 -option2
$ vnstat
Sample outputs:
rx / tx / total / estimated
eth1:
Oct '12 76.68 GiB / 635.07 GiB / 711.74 GiB
Nov '12 31.14 GiB / 186.98 GiB / 218.12 GiB / 352.45 GiB
yesterday 1.35 GiB / 11.32 GiB / 12.67 GiB
today 1.34 GiB / 8.82 GiB / 10.16 GiB / 19.37 GiB
eth0:
Oct '12 629.87 GiB / 91.10 GiB / 720.97 GiB
Nov '12 181.99 GiB / 35.38 GiB / 217.37 GiB / 351.24 GiB
yesterday 11.25 GiB / 1.70 GiB / 12.95 GiB
today 8.76 GiB / 1.60 GiB / 10.36 GiB / 19.76 GiB
To see eth0 stats, enter:
$ vnstat -i eth0
To see daily stats for eth0, enter:
$ vnstat -i eth0 -d
Sample outputs:
eth0 / daily
day rx | tx | total | avg. rate
------------------------+-------------+-------------+---------------
10/21/12 13.48 GiB | 1.80 GiB | 15.28 GiB | 1.48 Mbit/s
10/22/12 24.06 GiB | 3.44 GiB | 27.51 GiB | 2.67 Mbit/s
10/23/12 23.95 GiB | 3.45 GiB | 27.40 GiB | 2.66 Mbit/s
10/24/12 22.81 GiB | 3.30 GiB | 26.11 GiB | 2.53 Mbit/s
10/25/12 25.11 GiB | 3.48 GiB | 28.59 GiB | 2.78 Mbit/s
10/26/12 22.24 GiB | 3.01 GiB | 25.25 GiB | 2.45 Mbit/s
10/27/12 12.13 GiB | 1.67 GiB | 13.80 GiB | 1.34 Mbit/s
10/28/12 9.65 GiB | 1.67 GiB | 11.33 GiB | 1.10 Mbit/s
10/29/12 17.04 GiB | 3.13 GiB | 20.17 GiB | 1.96 Mbit/s
10/30/12 18.14 GiB | 3.18 GiB | 21.32 GiB | 2.07 Mbit/s
10/31/12 17.45 GiB | 3.05 GiB | 20.51 GiB | 1.99 Mbit/s
11/01/12 14.64 GiB | 2.74 GiB | 17.38 GiB | 1.69 Mbit/s
11/02/12 13.66 GiB | 2.51 GiB | 16.17 GiB | 1.57 Mbit/s
11/03/12 7.62 GiB | 1.34 GiB | 8.96 GiB | 870.25 kbit/s
11/04/12 5.63 GiB | 1.14 GiB | 6.77 GiB | 656.98 kbit/s
11/05/12 9.34 GiB | 2.08 GiB | 11.42 GiB | 1.11 Mbit/s
11/06/12 9.85 GiB | 2.13 GiB | 11.98 GiB | 1.16 Mbit/s
11/07/12 9.91 GiB | 2.14 GiB | 12.05 GiB | 1.17 Mbit/s
11/08/12 9.76 GiB | 2.12 GiB | 11.88 GiB | 1.15 Mbit/s
11/09/12 8.47 GiB | 1.81 GiB | 10.28 GiB | 998.23 kbit/s
11/10/12 5.54 GiB | 1.05 GiB | 6.58 GiB | 639.28 kbit/s
11/11/12 5.92 GiB | 1.12 GiB | 7.03 GiB | 682.98 kbit/s
11/12/12 8.74 GiB | 1.93 GiB | 10.67 GiB | 1.04 Mbit/s
11/13/12 8.77 GiB | 1.95 GiB | 10.72 GiB | 1.04 Mbit/s
11/14/12 8.93 GiB | 2.00 GiB | 10.93 GiB | 1.06 Mbit/s
11/15/12 10.53 GiB | 2.13 GiB | 12.65 GiB | 1.23 Mbit/s
11/16/12 13.58 GiB | 2.31 GiB | 15.89 GiB | 1.54 Mbit/s
11/17/12 11.09 GiB | 1.60 GiB | 12.70 GiB | 1.23 Mbit/s
11/18/12 11.25 GiB | 1.70 GiB | 12.95 GiB | 1.26 Mbit/s
11/19/12 8.81 GiB | 1.61 GiB | 10.42 GiB | 1.92 Mbit/s
------------------------+-------------+-------------+---------------
estimated 16.69 GiB | 3.06 GiB | 19.74 GiB |
To see hourly network stats, enter:
$ vnstat -i eth0 -h
To see monthly network stats, enter:
$ vnstat -i eth0 -m
To see weekly network stats, enter:
$ vnstat -i eth0 -w
To see top 10 network, stats:
$ vnstat -t
$ vnstat -i eth0 -t
To see short output:
$ vnstat -i eth0 -s
To calculate traffic, enter:
$ vnstat -i eth0 -tr
Sample outputs:
2038 packets sampled in 5 seconds Traffic average for eth0 rx 1.08 Mbit/s 202 packets/s tx 273.60 kbit/s 204 packets/s
To see transfer rate in real time for eth0, enter:
$ vnstat -i eth0 -l
Check out related media
This tutorial is also available in a video format:
(Video.01: Demo: Setup and use vnStat )
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This FAQ entry is 1 of 2 in the "vnStat Monitor and Log Network Traffic Tutorial" series. Keep reading the rest of the series:- Install vnStat Network Traffic Monitor To Keep a Log Of Daily Traffic
- View Vnstat Graphs Using PHP Web Interface Frontend
{ 4 comments… read them below or add one }
Hi,
Thanks, very useful material
Using Centos 6.3 and it uses em1 and lo.
I’ve entered em1 instead of eth0 and em2 instead of eth1. But vnstat says that there isn’t enough data available yet. It’s on a busy server.. Have I mixed the networkcards up?
Lo is the loopback interface. In otherwords, localhost, which points back to your machine. I dony know what em1 would be, but that’s not it either. Check ifconfig and iwconfig and see what your options are.
em1 is common name on BSD like operating system such as FreeBSD / OpenBSD and so on. I think newer Linux kernel are also started use the em1, em0 and so on.