Briefly, this error occurs when Elasticsearch cannot locate a readable index N file in a non-empty shard snapshot directory. This could be due to corruption or deletion of the index file. To resolve this issue, you can try restoring the index from a backup if available. If not, you may need to recreate the index. Additionally, ensure that Elasticsearch has the necessary permissions to access the directory. Lastly, check the health of your disk as hardware issues can also cause this error.
This guide will help you check for common problems that cause the log ” Could not find a readable index-N file in a non-empty shard snapshot directory [” + shardContainer.path() + “] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: container, snapshot, blobstore, shard, repositories.
Log Context
Log “Could not find a readable index-N file in a non-empty shard snapshot directory [” + shardContainer.path() + “]” classname is BlobStoreRepository.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :
final BlobStoreIndexShardSnapshots shardSnapshots =
INDEX_SHARD_SNAPSHOTS_FORMAT.read(shardContainer; Long.toString(latest); namedXContentRegistry; bigArrays);
return new Tuple(shardSnapshots; latest);
} else if (blobs.stream().anyMatch(b -> b.startsWith(SNAPSHOT_PREFIX) || b.startsWith(INDEX_FILE_PREFIX)
|| b.startsWith(UPLOADED_DATA_BLOB_PREFIX))) {
logger.warn("Could not find a readable index-N file in a non-empty shard snapshot directory [" + shardContainer.path() + "]");
}
return new Tuple(BlobStoreIndexShardSnapshots.EMPTY; latest);
}
/**
