NMS-16033: Update docs on default RRD

docs/modules/operation/pages/deep-dive/performance-data-collection/collectd/collection-packages.adoc

@@ -34,7 +34,9 @@ The following tags are also available for an interface filter:
 
 [cols="1,3,3"]
 |===
-| Tag | Description | Example
+| Tag
+| Description
+| Example
 
 | specific
 | Specify an actual IP address to include in the package.
@@ -70,6 +72,11 @@ The following example illustrates collector package attributes that use some of
 <3> Evaluate IPv4 rule to collect for all IPv4 interfaces in the given range.
 <4> Evaluate IPv6 rule to collect for all IPv6 interfaces in the given range.
 
+[[ga-rrd-retention]]
+== Default metric retention
+
+include::../../retention.adoc[]
+
 [[ga-collectd-packages-services]]
 == Service configuration attributes
 
@@ -104,7 +111,8 @@ For a list of collector-specific parameters and their default values, refer to t
 .Common service attributes
 [options="autowidth"]
 |===
-| Attribute | Description
+| Attribute
+| Description
 
 | name
 | Service name

docs/modules/operation/pages/deep-dive/retention.adoc

@@ -0,0 +1,34 @@
+When using RRD/JRB storage, data is stored in the file system using a RRD-type strategy.
+With this "round robin" storage, data is kept in aggregated time buckets, with the latest bucket overwriting the oldest bucket, and multiple collection within the time period for a bucket will cause the data to be consolidated based on the type of bucket.
+
+The aggregation buckets are defined in various config files based on a `<RRD>...</RRD>` block.
+
+.Default RRD config
+[source, xml]
+----
+<rrd step="300"><1>
+   <rra>RRA:AVERAGE:0.5:1:2016</rra><2>
+   <rra>RRA:AVERAGE:0.5:12:1488</rra><3>
+   <rra>RRA:AVERAGE:0.5:288:366</rra><4>
+   <rra>RRA:MAX:0.5:288:366</rra><5>
+   <rra>RRA:MIN:0.5:288:366</rra><6>
+</rrd>
+----
+<1> Step of 300 seconds (5 minutes) per bucket.
+This value should match the interval of the services in the package.
+<2> Store the average of 1 bucket for 2016 buckets.
+5 minute averages kept for 7 days.
+<3> Store the average of 12 buckets for 1488 buckets.
+1 hour average kept for 62 days.
+<4> Store the average of 288 buckets for 366 buckets.
+1 day average kept for 366 days.
+<5> Store the maximum of 288 buckets for 366 buckets.
+1 day max for kept 366 days.
+<6> Store the minimum of 288 buckets for 366 buckets.
+1 day min for kept 366 days.
+
+IMPORTANT: If the RRD definition is modified after data has been collected, the existing RRD/JRB files on disk must manually be deleted so they can be recreated with the updated definition.
+
+When using another storage strategy, such as Newts, Cortex, or other integration, all collected data points are persisted without aggregation.
+These points will be kept until the configured TTL expires.
+These storage strategies will ignore any defined `<RRA>` definitions in favor of the TTL value.

docs/modules/operation/pages/deep-dive/service-assurance/polling-packages.adoc

@@ -38,38 +38,7 @@ You can also exclude IP interfaces:
 
 == Response time configuration
 
-The definition of polling packages lets you configure similar services with different polling intervals.
-All the response time measurements are persisted in RRD files and require a definition.
-Each polling package contains an RRD definition:
-
-.RRD configuration for polling package
-[source, xml]
-----
-<package name="example1">
-  <filter>IPADDR != '0.0.0.0'</filter>
-  <include-range begin="1.1.1.1" end="254.254.254.254" />
-  <include-range begin="::1" end="ffff:ffff:ffff:ffff:ffff:ffff:ffff:ffff" />
-  <rrd step="300"> <1>
-    <rra>RRA:AVERAGE:0.5:1:2016</rra> <2>
-    <rra>RRA:AVERAGE:0.5:12:1488</rra> <3>
-    <rra>RRA:AVERAGE:0.5:288:366</rra> <4>
-    <rra>RRA:MAX:0.5:288:366</rra> <5>
-    <rra>RRA:MIN:0.5:288:366</rra> <6>
-</rrd>
-----
-
-<1> Polling interval for all services in this polling package is reflected in the step size of 300 seconds.
-All services in this package must be polled on a 5-minute interval, otherwise response time measurements are not persisted correctly.
-<2> 1 step size is persisted 2016 times: 1 * 5 min * 2016 = 7 d, 5 min accuracy for 7 d.
-<3> 12 steps average persistence 1488 times: 12 * 5 min * 1488 = 62 d, aggregated to 60 min for 62 d.
-<4> 288 steps average persistence 366 times: 288 * 5 min * 366 = 366 d, aggregated to 24 h for 366 d.
-<5> 288 steps maximum from 24 h persisted for 366 d.
-<6> 288 steps minimum from 24 h persisted for 366 d.
-
-WARNING: The RRD configuration and the service polling interval must be aligned.
-In other cases, the persisted response time data is not correctly displayed in the response time graph.
-
-IMPORTANT: If you change the polling interval afterwards, you must recreate existing RRD files with the new definitions.
+include::../retention.adoc[]
 
 == Service status persistence