Frequently Asked Questions


  1. What does NAR have to offer over other System Activity Reporters?

    NAR is the Network Activity Reporter. NAR monitors and collects network traffic volume data.

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  3. What type of data does NAR collect?

    NAR collects information about the traffic volume and the errors that have occured on all configured network devices on the system.

    Network Device Traffic - NAR monitors the number of bits, packets, broadcast packets, and multicast packets that travel in and out of the network devices.

    Network Device Errors - NAR watches for transmission and reception errors, collisions and queue length.

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  1. What system requirements are needed to run NAR?

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  3. What is required to run NAR?

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  5. How much space should I allocate for data collection?

    Roughly 3 MB per host per year for data storage, and another 1 MB per host for graph display. Systems with a large number of disk drives may require an additional 3 MB of space.

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  7. What Operating Systems are supported?

    The following table shows the operating systems support status as of Feb 2007.

    Operating SystemSupport
    Mac OSXSupported

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  1. If a machine is off the network, will the data still be collected and graphed? depends on what's "down".

    If the remote system is down, then no miscsar data is being collected.

    If the remote system is unreachable due to a network problem, MiscSAR will continue to collect data automatically.

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  3. Can you control how much data is collected and how long it is kept?

    Not easily.

    RRDTool requires data to be collected as specific intervals, or else the data is considered invalid. RRDTool also requires that storage is pre-allocated for the predicted size. These constraints also aid in the small processing over head of RRDTool.

    Five minute data collection intervals and storage of one year of data per host were chosen as the NARC limits based on input from colleagues and years of running monitoring tools.

    The intrepid programmer can dive into the NARC code to change these, if desired. This is not recommeneded. Or supported.

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  5. Does NAR run continually in the background on the clients?

    No. Each remote system collects data locally every 5 minutes.

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  7. Does NAR use up a lot of system resources on the clients?

    Resources on the clients (i.e., systems being monitored) are neglible (< 1% CPU utilitazation).

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  9. What about firewalls and the operation of NAR?

    Data collection for MiscSAR occurs locally and does not cross any network boundaries, so no firewalls should be encountered.

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  11. Why can't I load historical data?

    Is there data to be loaded? NAR data is pruned by crontab entries (see na2) every few weeks to avoid filling disks.

    Is there already data in the RRDTool database? RRDTool is a "forward only" database, not a random access database. This means that only data with newer time stamps may be inserted into the database. Attempts to load old data will raise RRDTool errors.

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Data Collection

  1. No data is being collected on the client. What's wrong?

    Make sure that NAR is enabled.

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