Identify the interface name and host
In Cacti go to 'New Graphs' Select the correct Host
In Graph Types select 'SNMP High Speed Interface Statistics'
In the search box type 'interface name' and press go
This will list the interfaces that match the name
Note down interface index number in the first column
In cacti go to System utilities → Click on 'View Poller cache'
Select the correct host and enter the interface index number in the search bar and click Go
Identify the data source and note down the RRD file number
In cacti click 'Data Sources' click any of the listed data sources
once displayed change the id number in the URL with the data source number
http://cacti.geant.net/cacti/data_sources.php?action=ds_edit&id=20895
note down the description of the data source 'lon-fra__InfiniCortex_TEIN-PSNC_15042'
In Cacti go to 'Graph Management'
Enter the host and in the search box 'description of the data source'
select the graph with error in description