elasticsearch/docs/reference/data-store-architecture.asciidoc

= Data store architecture

[partintro]
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{es} is a distributed document store. Instead of storing information as rows of columnar data, {es} stores complex data structures that have been serialized as JSON documents. When you have multiple {es} nodes in a cluster, stored documents are distributed across the cluster and can be accessed immediately
from any node.

The topics in this section provides information about the architecture of {es} and how it stores and retrieves data: 

* <<nodes-shards,Nodes and shards>>: Learn about the basic building blocks of an {es} cluster, including nodes, shards, primaries, and replicas.
* <<node-roles-overview,Node roles>>: Learn about the different roles that nodes can have in an {es} cluster.
* <<docs-replication,Reading and writing documents>>: Learn how {es} replicates read and write operations across shards and shard copies.
* <<shard-allocation-relocation-recovery,Shard allocation, relocation, and recovery>>: Learn how {es} allocates and balances shards across nodes.
** <<shard-allocation-awareness,Shard allocation awareness>>: Learn how to use custom node attributes to distribute shards across different racks or availability zones.
* <<shard-request-cache,Shard request cache>>: Learn how {es} caches search requests to improve performance.
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include::nodes-shards.asciidoc[]
include::node-roles.asciidoc[]
include::docs/data-replication.asciidoc[leveloffset=-1]
include::modules/shard-ops.asciidoc[]
include::modules/cluster/allocation_awareness.asciidoc[leveloffset=+1]
include::shard-request-cache.asciidoc[leveloffset=-1]