dsmiley commented on code in PR #4246: URL: https://github.com/apache/solr/pull/4246#discussion_r3007059648
########## solr/solr-ref-guide/modules/getting-started/pages/cluster-types.adoc: ########## @@ -0,0 +1,158 @@ += Solr Cluster Types +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +A Solr cluster is a group of servers that each run one or more Solr _nodes_. + +There are two general modes of operating a cluster of Solr nodes. +One mode provides central coordination of the Solr nodes (<<SolrCloud Mode>>), while the other allows you to operate a cluster without this central coordination (<<User-Managed Mode>>). + +TIP: "User Managed" and "Single Node" are sometimes referred to as "Standalone", especially in source code. + +Both modes share general concepts, but ultimately differ in how those concepts are reflected in functionality and features. + +First let's cover a few general concepts and then outline the differences between the two modes. + +== Cluster Concepts + +=== Servers and Nodes + +A _server_ is the hardware or virtual machine that hosts Solr software. +A _node_ is an instance of a running Solr process that services search and indexing requests. +Large servers may run multiple Solr nodes, though typically one node per server is most common. + +=== Shards + +In both cluster modes, a logical collection of documents can be divided across nodes as _shards_. +Each shard represents a logical slice of the overall collection and contains a subset of the documents. + +The number of shards determines the theoretical limit to the number of documents that can be stored. +It also dictates the amount of parallelization possible for an individual search request. + +=== Replicas + +A shard is a logical concept—a slice of your collection. +A _replica_ is the physical manifestation of that logical shard. +It is the actual running instance that holds and serves the documents belonging to that shard. Review Comment: > "likely" raises the question when does it not have an update log? Can we clarify when or omit? I think this page should be high level. It shouldn't delve into replica types, which would clarify a further answer to that. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
