[lucene-solr] 01/02: SOLR-12845: Update the RefGuide.

[ab...@apache.org]

This is an automated email from the ASF dual-hosted git repository.

ab pushed a commit to branch jira/solr-12845
in repository https://gitbox.apache.org/repos/asf/lucene-solr.git

commit cfa3853b2e6ac1b83bb42c8b242a9e22d57ed087
Author: Andrzej Bialecki <ab...@apache.org>
AuthorDate: Tue Apr 21 14:01:51 2020 +0200

    SOLR-12845: Update the RefGuide.
---
 .../src/solrcloud-autoscaling-overview.adoc         | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/solr/solr-ref-guide/src/solrcloud-autoscaling-overview.adoc b/solr/solr-ref-guide/src/solrcloud-autoscaling-overview.adoc
index b7c438c..8582e63 100644
--- a/solr/solr-ref-guide/src/solrcloud-autoscaling-overview.adoc
+++ b/solr/solr-ref-guide/src/solrcloud-autoscaling-overview.adoc
@@ -65,6 +65,27 @@ There are many metrics on which the rule can be based, e.g., system load average
 
 When a node, shard, or collection does not satisfy a policy rule, we call it a *violation*.   By default, cluster management operations will fail if there is even one violation.  You can allow operations to succeed in the face of a violation by marking the corresponding rule with <<solrcloud-autoscaling-policy-preferences.adoc#rule-strictness,`"strict":false`>>.  When you do this, Solr ensures that cluster management operations minimize the number of violations.
 
+The default cluster policy, if none is specified, is the following:
+
+[source,json]
+----
+[
+  { "replica" : "<2", "shard" : "#EACH", "node" : "#ANY", "strict" : false},
+  { "replica" : "#EQUAL", "node" : "#ANY", "strict" : false},
+  { "cores" : "#EQUAL", "node" : "#ANY", "strict" : false}
+]
+----
+
+These rules mean that:
+
+* Each shard should not have more than one replica on the same node, if possible (strict: false).
+* Each collection's replicas should be equally distributed among nodes.
+* All cores should be equally distributed among nodes.
+
+
+NOTE: You can remove this default policy by specifying an empty rule-set in the autoscaling
+admin request, like this: `{set-cluster-policy : []}`.
+
 Solr also supports <<solrcloud-autoscaling-policy-preferences.adoc#collection-specific-policy,collection-specific policies>>, which operate in tandem with the cluster policy.
 
 == Triggers