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Elassandra

elassandra.org

LinuxAPISelf-hosted
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Spec score 7.3 #10 of 22 in Wide-Column Databases

What it is

Elassandra combines Apache Cassandra’s distributed storage with embedded OpenSearch search on each node. Its maintained line targets Apache Cassandra 4.0.x, OpenSearch 1.3.x, and Java 11. OpenSearch indices map to Cassandra keyspaces, documents to rows, and indexed fields to columns or cells; the current _doc model maps to a Cassandra table. Cassandra remains the durable layer, allowing restart recovery to replay Cassandra state and rebuild a local search view. Applications can search through the OpenSearch HTTP API or CQL, with HTTP responses following OpenSearch style. Data placement uses Cassandra token ownership, while replicas follow keyspace replication. Schemas can be created from OpenSearch indexes or discovered from existing Cassandra schemas through mappings. Integrations listed include OpenSearch plugins, OpenSearch Dashboards, and Spark. Deployment options include tarball, Debian package, RPM, Docker image, and Helm chart. Elassandra is free and open source, with a 30-day trial noted.

Spec sheet

What it does
Elassandra embeds OpenSearch inside Apache Cassandra so each node serves distributed storage and distributed search.Read 3 Oct 2026 · elassandra.org
Purpose
Elassandra embeds OpenSearch inside Apache Cassandra so each node provides distributed storage and distributed search.Read 3 Oct 2026 · elassandra.org
Deployment
The documentation lists tarball, Debian package, RPM, Docker image, and Helm chart installation options.Read 3 Oct 2026 · elassandra.org
Integrations
The documentation lists integration with OpenSearch plugins, OpenSearch Dashboards, and Spark.Read 3 Oct 2026 · elassandra.org
APIs
Elassandra exposes Cassandra-backed documents through OpenSearch-compatible HTTP APIs and also supports searching through CQL.Read 3 Oct 2026 · elassandra.org
Consistency limit
Document version fields such as _version, _seq_no, and _primary_term are not globally authoritative conflict controls.Read 3 Oct 2026 · elassandra.org
Current stack
The maintained line targets Apache Cassandra 4.0.x, OpenSearch 1.3.x, and Java 11.Read 3 Oct 2026 · elassandra.org
Data durability
Cassandra is the durable storage layer, and Elassandra rebuilds the local search view from Cassandra state when needed.Read 3 Oct 2026 · elassandra.org
Data model
Elassandra maps OpenSearch indices to Cassandra keyspaces, documents to rows, and indexed fields to columns or cells.Read 3 Oct 2026 · elassandra.org
Deployment options
The documentation lists tarball, Debian package, RPM, Docker image, and Helm chart installation options.Read 3 Oct 2026 · elassandra.org
Durability
Cassandra is the durable storage layer, and restart recovery replays Cassandra state and can rebuild the local search view.Read 3 Oct 2026 · elassandra.org
Feature scope
The current line focuses on embedded OpenSearch, and the documentation advises validating advanced upstream features before relying on them in production.Read 3 Oct 2026 · elassandra.org
Index deletion limit
Deleting an index removes search metadata and files but does not delete its backing Cassandra keyspace or table by default.Read 3 Oct 2026 · elassandra.org
Local resource guidance
The quick start says each node usually needs around 1.5 GB to 2 GB of RAM for local demos.Read 3 Oct 2026 · elassandra.org
Maintained stack
The documented maintained line targets Apache Cassandra 4.0.x, OpenSearch 1.3.x, and Java 11.Read 3 Oct 2026 · elassandra.org
Operational limit
Elassandra requires the Murmur3 partitioner, and search indexing adds work to Cassandra writes, especially for complex documents.Read 3 Oct 2026 · elassandra.org
Operational requirement
Elassandra requires the Murmur3 partitioner.Read 3 Oct 2026 · elassandra.org
Refresh trade-off
Immediate search visibility after a write trades off against write latency, and synchronous refresh adds cost.Read 3 Oct 2026 · elassandra.org
Scaling
Data placement follows Cassandra token ownership, and replica behavior follows Cassandra keyspace replication.Read 3 Oct 2026 · elassandra.org
Schema workflows
Elassandra supports creating Cassandra schema from an OpenSearch index or discovering an existing Cassandra schema through OpenSearch mappings.Read 3 Oct 2026 · elassandra.org
Search and storage mapping
An OpenSearch index maps to a Cassandra keyspace, and the current `_doc` model maps to a Cassandra table.Read 3 Oct 2026 · elassandra.org
Search freshness
Refresh scheduling is separate from Cassandra replication, so immediate search visibility trades off against write latency.Read 3 Oct 2026 · elassandra.org
Search interfaces
Search requests can use the OpenSearch HTTP API or CQL, and Elassandra returns standard OpenSearch-style search responses.Read 3 Oct 2026 · elassandra.org

Strong points and limits

Strong points

  • Distributed storage and search in each node
  • OpenSearch HTTP API and CQL queries
  • Multiple package and container deployment options
  • Integrations with Dashboards, plugins, and Spark
  • Horizontal scaling and multi-region support

Limits

  • Requires the Murmur3 partitioner
  • Index deletion leaves backing Cassandra data by default
  • Immediate refresh can increase write latency
  • Advanced upstream features require validation

Who it suits

Elassandra suits teams wanting self-hosted distributed storage and search through Cassandra and OpenSearch interfaces. It fits deployments that can operate the Murmur3 partitioner and Cassandra-based scaling model.

Verdict

Elassandra provides Cassandra durability with OpenSearch-compatible search and several deployment paths. Its operational constraints around partitioning, refresh timing, deletion behavior, and feature validation deserve planning.

Where Specifiction places it

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