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TheWitness
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* Updating Copyrights and 4 new sections * Syntax issue with Copyright * Removing .travis.yml * Fixing some case and path informaiton
70 lines
2.9 KiB
Markdown
70 lines
2.9 KiB
Markdown
# Spike Kill
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Certain types of RRDtool based **Data Sources** can from time to time generate
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what are look like to the casual observer spikes. These spikes can make your
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Cacti **Graphs** unreadable.
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Spike happen when you either have set no maximum value on your Cacti **Data
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Template** by using a 'U' as the Maximum Value, or when certain `COUNTER` based
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RRDfiles have their counter data overflow, and start counting again from zero.
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When this happens recent versions of RRDtool, like version 1.7, handle these
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overflows quite well, but for some older RRDtool versions, these changes can
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result in these spikes.
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There are also cases where for some reason the Cacti system goes offline, and
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therefore your Cacti Graphs will develop what are referred to as gaps.
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## Spike Kill Settings
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Cacti provides two gap filling options from the user interface. In the image
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below, you can see the default Settings for Cacti's Spike Killer GUI.
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Those settings include:
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- **Removal Method** - Cacti supports both Variance and Standard Deviation
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methods. When calculating those values, you have the ability to filter out
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outliers such that they don't negatively impact those calculations.
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- **Replacement Method** - When filling the Gap, what data point should be used.
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There is `Last Known Good`, which would be the last good known value,
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`Average`, which uses the Average value for the RRDfile data source, and
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`NaN's` which will cause the **Graph** to gap, but the spikes will be removed.
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- **Number of Standard Deviations** - This is the number of
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`Standard Deviations` above the Average that are required before the value is
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considered a spike. It only applies to the `Standard Deviation` spike removal
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method.
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- **Variance Percentage** - When using the `Variance` spike detection method,
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the percentage above variance before considering a value a spike.
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- **Variance Number of Outliers** - The number of high values to ignore when
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calculating the Variance.
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- **Max Kills Per RRA** - The maximum number of spike to remove from any given
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RRDfile Data Source.
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- **RRDfile Backup Directory** - If you wish to backup RRDfiles that have been
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altered by Spike Kill, they will be placed in this directory.
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## Batch Spike Kill Settings
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Cacti also allows administrators to kill Cacti spikes on a periodic basis using
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a batch process. From this batch process, you select the time of day, the
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**Graph Templates** to perform Spike Kill operations on, and the backup
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retention for RRDfiles that have spikes removed from them. The image below shows
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those settings.
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Of note is that first of all, the only **Graph Templates** that are shown are
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**Graph Templates** that include `COUNTER` type **Data Sources**. It is also
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worth noting that only **Data Query** type **Graph Templates** are supported as
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of the current Cacti version.
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---
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Copyright (c) 2004-2026 The Cacti Group
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