Unable to resolve shard id Wrong folder structure at – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-7.15

Briefly, this error occurs when Elasticsearch cannot identify the shard ID due to an incorrect folder structure. This could be due to a manual change in the data directory or a failed migration. To resolve this, ensure the data directory structure aligns with Elasticsearch’s expectations. If a migration was attempted, retry it ensuring all steps are correctly followed. If the issue persists, consider restoring from a backup. Always remember to backup your data before making significant changes to prevent data loss.

This guide will help you check for common problems that cause the log ” Unable to resolve shard id. Wrong folder structure at [ ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: shard, index.

Log Context

Log “Unable to resolve shard id. Wrong folder structure at [” class name is RemoveCorruptedShardDataCommand.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 indexMetadata = StreamSupport.stream(clusterState.metadata().indices().values().spliterator(); false)
 .map(imd -> imd.value)
 .filter(imd -> imd.getIndexUUID().equals(indexUUIDFolderName)).findFirst()
 } else {
 throw new ElasticsearchException("Unable to resolve shard id. Wrong folder structure at [ " + path.toString()
 + " ]; expected .../nodes/[NODE-ID]/indices/[INDEX-UUID]/[SHARD-ID]");
 } else {
 // otherwise resolve shardPath based on the index name and shard id
 String indexName = Objects.requireNonNull(indexNameOption.value(options); "Index name is required");