Data Settings

Settings-Data.md

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 # Data Settings
 
+The Cacti Data settings includes settings for gathering statistical data
+about Cacti's **Data Sources** and about settings around how Cacti
+stores it's **Round Robin Archives** Time Series Databases (TSDB),
+otherwise known as RRDfiles.
+
+There are presently to sub-sections for these settings.
+
+## Data Source Statistics
+
+Cacti has the ability to store peak and average data for all your 
+**Data Sources**.  You can then use that data to easily build
+dashboards using third party plugins including plugins like
+Superlinks from Howard Jones.
+
+Below you will find an image of the default settings.
+
+![Data Source Statistics](images/settings-data-source-statistics.png)
+
+Those settings include:
+
+- **Enable Data Source Statistics Collection** - This is setting
+  will either enable or disable the statistics collection.
+
+- **Daily Update Frequency** - This setting determines how often
+  daily averages and peaks should be calculated.  You can set
+  it to run hourly, upto every 6 hours, or after Cacti's boost
+  process completes.
+
+- **Hourly Average Window** - This is a floating time window where
+  Cacti holds onto all samples for determining the hourly averages
+  for your **Data Sources**.  You have to watch this cache as by
+  default it's stored in a memory table.  You can run out of space.
+
+- **Maintenance Time** - This is the time in the day that Cacti
+  will calculate Monthly and Yearly numbers and perform table
+  maintenance.
+
+- **Memory Limit for Data Source Statistics Data Collector** - This
+  setting controls the peak memory that the statistics poller
+  will be allowed to use.  Most systems can work fine using the
+  default 1GByte setting.
+
+## Data Storage Settings
+
+These settings determine how you store your RRDfiles.  This
+sub-section has two layouts as showing in the images below.
+
+![Data Storage Local](images/settings-data-local.png)
+
+The settings above include:
+
+- **Location** - Either Local or RRDtool Proxy Server.  The example
+  above shows the local storage option.
+
+- **Structured RRD Paths** - In very large systems having a flat
+  directory structure has severe performance consequences.  However,
+  with the Structured Paths option, Cacti will separate RRDfiles by
+  Device ID and use the Data Source ID as the RRDfile name.
+
+> **NOTE**: If you are migrating from non-structured to structured
+> paths setup, you must run the CLI script to move those files
+> per the updated specification right after making this change.
+
+The RRD Proxy settings below are more involved.
+
+> **NOTE**: It should be noted that although the RRD Proxy is
+> in production at large commercial sites, it continues to not
+> support replication.  The author claims that it's 95%
+> complete, but to date, has not completed the last 5%.
+
+![Data Storage Proxy](images/settings-data-proxy.png)
+
+The settings above include:
+
+- **Proxy Server** - The IP or DNS name of the primary RRDfile proxy
+  server.
+
+- **Proxy Port Number** - The port number to connect to in order to
+  communicate with the RRD Proxy.
+
+- **RSA Fingerprint** - The fingerprint of the current public RSA
+  key the proxy is using.  This is required to establish a trusted
+  connection to the RRD Proxy service.
+
+> **WARNING**: None of the settings below are implemented.
+
+- **Load Balancing** - Whether calls to the RRD Proxy should be
+  load balanced.
+
+- **Proxy Server** - The secondary Proxy server IP or DNS name.
+
+- **Proxy Port Numer** - The port number on the secondary RRD Proxy
+  to talk to.
+
+- **RSA Fingerprint** - The fingerprint of the current public RSA
+  key the proxy is using.  This is required to establish a trusted
+  connection to the RRD Proxy service.
+
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