Add the Overview article draft

Author: patiencedaur

conf.py

@@ -21,6 +21,7 @@
     'sphinx.ext.ifconfig',
     'sphinx.ext.intersphinx',
     'sphinx.ext.extlinks',
+    'sphinx_panels',
     'sphinxcontrib.plantuml',
     'ext.custom',
     'ext.LuaDomain',

doc/overview.rst

@@ -0,0 +1,132 @@
+Overview
+========
+
+What is Tarantool?
+------------------
+
+Tarantool combines an in-memory DBMS and a Lua server in a single platform, which
+provides ACID-compliant storage. It comes in :ref:`open-source and commercial editions <overview-editions>`.
+The :ref:`use cases <overview-use_cases>` for Tarantool vary from ultra-fast cache
+to product data marts and smart queue services.
+
+Here are some of Tarantool's key characteristics:
+
+..  panels::
+    :container: doc-cards
+    :column: doc-card doc-card_big
+    :card: doc-card__content
+    :header: doc-card__title
+    :body: doc-card__text
+
+    Row-based storage data
+    ^^^^^^^^^^^^^^^^^^^^^^
+    Data is stored in tuples
+    ---
+    Easy handling of OLTP workloads
+    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+    Processes hundreds of thousands RPS
+    ---
+    Data integrity
+    ^^^^^^^^^^^^^^
+    Write-ahead log (WAL) and data snapshots 
+    ---
+    Cooperative multitasking
+    ^^^^^^^^^^^^^^^^^^^^^^^^
+    Transactions are performed in lightweight coroutines with no interthread locking
+    ---
+    Advanced indexing
+    ^^^^^^^^^^^^^^^^^
+    Composite indexes, locale support, indexing by nested fields and arrays
+    ---
+    Compute close to data
+    ^^^^^^^^^^^^^^^^^^^^^
+    Lua server and Just-In-Time compiler on board
+    ---
+    Durable replication
+    ^^^^^^^^^^^^^^^^^^^
+    Multiple failover modes and RAFT-based synchronous replication available
+
+Tarantool allows executing code alongside data, which helps increase the speed of operations.
+Developers can implement any business logic with Lua,
+and a single Tarantool instance can also receive SQL requests.
+
+Tarantool has a variety of compatible `modules <https://www.tarantool.io/en/download/rocks>`__ (Lua rocks).
+You can pick the ones that you need and install them manually.
+
+Tarantool runs on Linux (x86_64, aarch64), Mac OS X (x86_64, M1), and FreeBSD (x86_64).
+
+You can use Tarantool with a programming language you're familiar with.
+For this purpose, a number of :ref:`connectors <getting_started_connectors>` are provided.
+
+..  _overview-editions:
+
+Editions
+--------
+
+Tarantool comes in two editions: the open-source **Community Edition (CE)**
+and the commercial **Enterprise Edition (EE)**.
+
+**Tarantool CE** lets you develop applications and speed up a system in operation.
+It features :ref:`synchronous replication <repl_sync>`, affords easy :ref:`scalability <sharding>`,
+and includes tools to develop efficient :ref:`applications <app_server>`.
+The `Tarantool community <https://t.me/tarantool>`__ helps with any practical questions
+regarding the Community Edition.
+
+**Tarantool EE** `provides advanced tools <https://www.tarantool.io/en/compare/>`__ for
+administration, deployment, and security management, along with premium support services.
+This edition includes all the Community Edition features
+and is more predictable in terms of solution cost and maintenance.
+The Enterprise Edition is shipped as an SDK and includes a number of closed-source modules.
+See the `documentation for Tarantool EE <https://www.tarantool.io/en/enterprise_doc/>`__.
+
+For a focus on business logic, try `Tarantool Data Grid <https://www.tarantool.io/en/datagrid/>`__ --
+a data integration tool with a web GUI perfectly suitable for non-programmers.
+Tarantool Data Grid is also based on the Community Edition.
+See the `documentation for Tarantool Data Grid <https://www.tarantool.io/en/tdg/1.6/>`__.
+
+..  _overview-use_cases:
+
+Use cases
+---------
+
+Fast first-class storage
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+*   Primary storage
+
+    -   No secondary storage required
+
+*   Tolerance to high write loads
+*   Support of relational approaches
+*   Composite secondary indexes
+
+    -   Data access, data slices
+
+*   Predictable request latency
+*   Read available even when the disk is down
+
+Advanced cache
+~~~~~~~~~~~~~~
+
+*   Write-behind caching
+*   Secondary index support
+*   Complex invalidation algorithm support
+
+Smart queue
+~~~~~~~~~~~
+
+*   Support of various identification techniques
+*   Advanced task lifecycle management
+
+    -   Task scheduling
+    -   Archiving of completed tasks
+
+Data-centric applications
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+*   Arbitrary data flows from many sources
+*   Incoming data processing
+*   Storage
+*   Background cycle processing
+
+    -   Scheduling support