I have to re-learn this every time I setup a new system so here is the basics for setting up bandwidth graphs with cacti. This assumes a RHEL/Centos/SL 6 installation.

1. Create a cacti snmp user in /etc/snmp/snmpd.conf

    com2sec cactiUser  default       your-community-string-goes-here
    group   cactiGroup v1           cactiUser
    group   cactiGroup v2c           cactiUser
    view    allview    included   .1
    access  cactiGroup ""      any       noauth    exact  allview none none
   

2. Start snmpd

    service start snmpd
    chkconfig snpds on
   

3. Install net-snmp-utils

    yum install net-snmp-utils
   

4. Install Cacti

    yum install cacti
   

5. Create MySQL DB and user (this may be done for you by the cacti RPM I’m not sure)

    mysqladmin create cacti
    mysql < /usr/share/doc/cacti-0.8.8a/cacti.sql
    mysql mysql
    mysql> GRANT ALL ON cacti.* TO cactiuser@localhost IDENTIFIED BY 'somepassword';
    mysql> flush privileges;
   

6. Configure /etc/cacti/db.php with the password you setup in the DB
7. Edit /etc/cron.d/cacti and uncomment the poller.php line by deleting the leading “#” charcter
8. Edit /etc/httpd/conf.d/cacti.conf to Allow your IP address to access the web UI
9. Browse to http://example.com/cacti/ and do the initial config
10. Log in as admin/admin
11. Set the admin password
12. Browse to “Devices” : http://example.com/cacti/host.php
13. “Localhost” : http://example.com/cacti/host.php?action=edit&id=1
14. Change “SNMP Version” from “Not In Use” to “Version 2”
15. Change “SNMP Community” to the your-community-string-goes-here that you set in snmpd
16. Click “Save”
17. Under “Associated Data Queries”… “Add Data Query”
18. Select “SNMP - Interface Statistics”
19. Click “Add”
20. Click “Create Graphs for this host” : http://example.com/cacti/graphs_new.php?host_id=1
    • Under “Data Query” check the checkbox on the far right next to eth0
21. In the “Select a graph type” select “In/Out Bits with 95th percentile”
22. Click “Create”
23. Wait 5 minutes while cron calls the poller and generates the first data for graph rendering