NetFlow Raw Data Settings
NetFlow Analyzer classifies data into 2 types namely Aggregated Data
and the Raw Data.
Aggregated Data represents the total IN and OUT traffic, the top 100 application and the top 100 conversation for each interface for every 10 minute intervals. Data is progressively stored in 10 minute, 1 hour, 6 hour, 24 hour and weekly data points for older data - the most recent data is available with 10 minute granularity and data older than 90 days is available in weekly granularity.
This mechanism of storing the top 100 is done to ensure that the database
does not grow infinitely. The amount of hard disk space required to store
the aggregated data forever is about 150 MB per interface.
In addition to the aggregated data, NetFlow Analyzer 5 allows you to store all raw netflow data for up to 1 month. The time period for which you can store this raw data (Raw Data Period) depends on the number of flows received by NetFlow Analyzer and the amount of free disk space available on your computer. Each flow is about 60 bytes. Troubleshooting and Alert reports are generated from Raw data since it provides high level of granularity.
NetFlow Analyzer indicates the flows received per second in the Raw
Data Settings tab on the Settings link. You should set the raw data period
( Retain Raw Data ) based on the calculation below:
Free hard disk space - (150 MB * No. of Managed Interfaces)
Raw Data Period (in hours) = ----------------------------------------------------------------------------------------
60 Bytes * 3600 seconds * Flows Per Second
You can use the recommendation provided by the software to set your Raw data storage period. The maximum raw data storage period is 1 month and the minimum is a day. Similar to the alerting feature, you can choose to have a mail sent whenever the disk space is less than a threshold value( This is set as a percentage value). In addition you can specify the free disk space threshold below which old raw data will be cleared up. This could be as percentage value of the total disk space. This can also take on the value of "Never", in which case the disk place is not cleared up at all.
One minute Data-Storage Settings
To set the period for which one minute flow data has to be stored use the Retain One Minute Data option. You could choose one of 1 month, 3 months, 6 months or 1 year. You will require a free disk space of 2MB to store one month of one minute traffic data for a single interface. The default period is 3 Months.
NBAR Data-Storage Settings
You can use this option to specify the time period for which NBAR data has to be retained. You could retain the NBAR data a minimum of 1 day or a maximum of 1 year. You will require a free disk space of 30 MB in order to store NBAR data for a month for each interface. The default value is 2 months.
Click on the "Update" button for the settings to take effect.