84 lines
3.4 KiB
Markdown
84 lines
3.4 KiB
Markdown
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---
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layout: default
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title: Segment replication configuration
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nav_order: 12
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parent: Segment replication
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grand_parent: Availability and Recovery
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---
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# Segment replication configuration
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Segment replication is an experimental feature. Therefore, we do not recommend the use of segment replication in a production environment. For updates on the progress of segment replication or if you want to leave feedback that could help improve the feature, see the [Segment replication issue](https://github.com/opensearch-project/OpenSearch/issues/2194).
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{: .warning }
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To enable the segment replication type, reference the steps below.
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## Enabling the feature flag
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There are several methods for enabling segment replication, depending on the install type. You will also need to set the replication strategy to `SEGMENT` when creating the index.
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### Enable on a node using a tarball install
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The flag is toggled using a new jvm parameter that is set either in `OPENSEARCH_JAVA_OPTS` or in config/jvm.options.
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1. Option 1: Update config/jvm.options by adding the following line:
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````json
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-Dopensearch.experimental.feature.replication_type.enabled=true
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````
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1. Option 2: Use the `OPENSEARCH_JAVA_OPTS` environment variable:
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````json
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export OPENSEARCH_JAVA_OPTS="-Dopensearch.experimental.feature.replication_type.enabled=true"
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````
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1. Option 3: For developers using Gradle, update run.gradle by adding the following lines:
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````json
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testClusters {
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runTask {
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testDistribution = 'archive'
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if (numZones > 1) numberOfZones = numZones
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if (numNodes > 1) numberOfNodes = numNodes
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systemProperty 'opensearch.experimental.feature.replication_type.enabled', 'true'
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}
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}
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````
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### Enable with Docker containers
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If you're running Docker, add the following line to docker-compose.yml underneath the `opensearch-node` and `environment` section:
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````json
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OPENSEARCH_JAVA_OPTS="-Dopensearch.experimental.feature.replication_type.enabled=true" # Enables segment replication
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````
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### Setting the replication strategy on the index
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To set the replication strategy to segment replication, create an index with replication.type set to `SEGMENT`:
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````json
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PUT /my-index1
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{
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"settings": {
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"index": {
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"replication.type": "SEGMENT"
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}
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}
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}
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````
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## Known limitations
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1. Enabling segment replication for an existing index requires [reindexing](https://github.com/opensearch-project/OpenSearch/issues/3685).
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1. Rolling upgrades are currently not supported. Full cluster restarts are required when upgrading indexes using segment replication. [Issue 3881](https://github.com/opensearch-project/OpenSearch/issues/3881).
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1. [Cross-cluster replication](https://github.com/opensearch-project/OpenSearch/issues/4090) does not currently use segment replication to copy between clusters.
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1. Increased network congestion on primary shards. [Issue - Optimize network bandwidth on primary shards](https://github.com/opensearch-project/OpenSearch/issues/4245).
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1. Shard allocation algorithms have not been updated to evenly spread primary shards across nodes.
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1. Integration with remote-backed storage as the source of replication is [currently unsupported](https://github.com/opensearch-project/OpenSearch/issues/4448).
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### Further resources regarding segment replication
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1. [Known issues](https://github.com/opensearch-project/OpenSearch/issues/2194).
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1. Steps for testing (link coming soon).
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1. Segment replication blog post (link coming soon).
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