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  1. #1
    Untangler
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    Default Bandwidth Control reports not scaling properly

    I am surprised I didn't see this earlier, but on my 2 Untangle boxes on 15.1, the Bandwidth Control default "Top xxx Usage" reports don't scale correctly with time when changing the "since" box. The bandwidth reported seems correct for "Since 1hr ago", but they are too high for any larger period of time.

    Untangle_BWCtrl.png

    I dug into the reports configuration, and all these use "Approximation = Sum (default)", which seems incorrect for a data rates (should be "high" like in other reports).
    Last edited by LaurentR; 08-11-2020 at 07:08 PM.

  2. #2
    Untangle Ninja Jim.Alles's Avatar
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    Default

    I agree that it can be disconcerting.

    This thread contains both an explanation from me, and an explanation from support.
    https://forums.untangle.com/reports/42851-scale-side-graphs-often-misleading.html
    You be the judge.
    Last edited by Jim.Alles; 08-12-2020 at 12:08 PM.

  3. #3
    Untangler
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    Thank you for the link!

    I am trying understand the support response but I don't quite get how their answer maps to the problem. Some of the content of the thread also leaves me perplexed.

    IMHO, the settings for Application Control reports are incorrect, as evidenced by other bytes/s graphs, which do scale correctly and use settings that make sense and there is an easy fix that resolves the scaling issue.

    How the graph works
    - It uses the "session_minutes" table, so it gets a sample point (in bytes) per minute.
    - The "(s2c_bytes+c2s_bytes)/60" formula just converts a total byte value (for a minute) to bytes/s (nothing to do with hours).
    - If you scroll over the graphs, you can tell that the "Since 1hr" graph directly uses the 60 points pulled from the table (one per minute) and display a smoothed version of it.
    - When using longer than "Since 1hr", the report engine groups multiple sample points together (hover over the graph, you'll see it groups by 5 minutes for 3/6 hours, 15min for 12hr and 30min for 24hr). As per the documentation, it does this by using the "Approximation" setting (from the wiki: "The method used to aggregate/combine data points").

    The sampling is different based on graph width. The values above are for the Medium dashboard widgets on my screen. I would guess the sampling in the thread picture was 2x since the values are 2x off (simple to check by hovering over the graph).

    Note that the support response and the thread mention things being "averaged by hour", but I don't see anything averaged by hour here. There is per minute sampling and then sample grouping as needed to display the graph when zoomed out enough, but that's it.

    If you want to finish convincing yourself that there is nothing magic about "Since: 1hr", go to the dashboard and shrink the widget to small. On my screen, it goes into 2x sampling and scales the Y axis 2x as a result.

    How this applies to the issue

    All the "Bandwidth Control" bytes/s reports use "Approximation: Sum", which doesn't make sense as it _adds_ sample points (which doesn't work when scaling things per second) and leads to problem shown here. You can see the mathematical results clearly as 3/6hr graphs are x5 (5 sample minutes), the 12hr graph is x15 (and the thread's graph seems to be x2)...

    All of the other reports in bytes/s (e.g. Application Control Usage) correctly use "Approximation: High" and as a result, they do scale correctly.

    One may argue whether "high" is better than "average" or not (filtering question), but it is clearly a reasonable choice while "Sum" is not.

    Conclusion

    My current bottom line is that the Bandwidth Control default reports have an incorrect setting for the Approximation field. I have reread the support response in that light and I still don't understand it.

    There are at least one more set of reports (Sessions per minute/hour) which also use the incorrect "Sum" method and don't scale properly. There might be more.
    Last edited by LaurentR; 08-12-2020 at 06:35 PM.

  4. #4
    Untangle Ninja Jim.Alles's Avatar
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    Thank you for taking the effort to dig into this. I have never bothered; even though if I let it, it would drive me bonkers.
    A good part of my career (HVAC controls) has been setting up, understanding and analyzing trends - then taking corrective action based on them...

    This just isn't all that. Untangle does need to pay more attention to the underlying math, IMHO

    It seems that you are able to get better results from custom reports.
    There would be nothing wrong with you opening a support ticket for this issue.
    I have entered a feature request, and will supply a link when it is moderator accepted.

  5. #5
    Untangler
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    Default

    Thanks.
    As per https://forums.untangle.com/announce...g-reports.html

    I'll wait to see if an untangle employee wants to pick this up from here. If not, I'll open a support ticket in a few days.

    I'll also respond to the thread you linked to as there is an easy fix for the OP until UT fixes this permanently (I guess not - the thread is closed - I didn't know it was a thing around here).

    Laurent
    Last edited by LaurentR; 08-12-2020 at 04:09 PM.
    Jim.Alles likes this.

  6. #6
    Untangler
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    Default

    Looking for something else report-related, I also found this old thread which could be explained by the same issue:

    https://forums.untangle.com/feedback...-s-bits-s.html

    OP complains about "Top Hostname Usage" being about 8x off, and since other widgets seemed to work, he may also have been a victim of the incorrect scaling.

    There are several other threads with the same symptoms, which may or may not be related to this (much older version of the dashboard):

    https://forums.untangle.com/feedback...ith-usage.html
    Last edited by LaurentR; 08-12-2020 at 06:36 PM.

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