Help Center/ Cloud Search Service/ FAQs/ General Consulting/ Differences Between Elasticsearch and OpenSearch
Updated on 2025-07-25 GMT+08:00
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Differences Between Elasticsearch and OpenSearch

CSS provides a fully managed cloud search service based on open-source engines. CSS Elasticsearch and OpenSearch both have the following core capabilities:
  • Unified architecture: a distributed, RESTful search engine, supporting near-real-time search and analytics over petabytes of data
  • A wide range of use cases: log analytics, enterprise search, big data analytics, vector search, semantic search, RAG, etc.
  • Enhanced features: deep optimization based on open-source versions, high performance, high availability, cost effective, and fully managed

A Comparison of Core Functions

Table 1 A comparison of core functions between Elasticsearch and OpenSearch

Dimension

CSS Elasticsearch

CSS OpenSearch

Origin

Built on Apache Lucene, Elasticsearch is a mature, widely adopted search engine.

OpenSearch, a fork of Elasticsearch, inherits its core search and analytics capabilities while keeps evolving.

Compatibility
  • Compatible with the Elasticsearch ecosystem
  • Compatible with later-version Elasticsearch SDKs
  • Compatible with the OpenSearch ecosystem
  • Compatible with Elasticsearch 7.10.2

Version policy

The mainstream version is 7.10.2, which will be continuously optimized. We recommend upgrading all Elasticsearch clusters to this version.

The version will be continuously updated to keep up with open-source innovations.

Kernel features

CSS will provide continuous kernel enhancement powered by in-house R&D.

CSS will integrate its own capabilities with open-source innovations to ensure continuous kernel enhancement.

Evolution

Emphasizes the stability of the 7.x version and in-house enhancements.

Actively integrates new cloud native features.

Engine Selection Suggestions

Table 2 When to choose Elasticsearch or OpenSearch

Scenario

Recommended Engine

Reason

Running Elasticsearch 7.10.2 or earlier for long-term stability

Elasticsearch
  • Mature and stable, fully compatible with the native Elasticsearch toolchain
  • Compatible with later-version Elasticsearch SDKs
  • Backed by the unique strengths of CSS (such as vector search)

New features of Elasticsearch 8+ are required

OpenSearch
  • Inherits Elasticsearch capabilities while keeps evolving
  • Backed by the unique strengths of CSS (such as vector search)

Smooth migration of existing Elasticsearch 7.x clusters

Elasticsearch or OpenSearch

Both are compatible with Elasticsearch 7.10.2 APIs, with a similar migration cost.
Parent topic: General Consulting