Briefly, this error occurs when Elasticsearch tries to delete files but fails because it cannot list the directory. This could be due to insufficient permissions, a locked file, or a file system issue. To resolve this, you can manually delete the files if they are no longer needed. If the issue persists, check the file permissions and ensure Elasticsearch has the necessary access. Also, verify that no other processes are locking the files. Lastly, check the health of your file system to rule out any underlying issues.
This guide will help you check for common problems that cause the log ” [{}] [{}] failed to list directory – some of files might not be deleted ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: repositories, blobstore.
Overview
An Elasticsearch snapshot provides a backup mechanism that takes the current state and data in the cluster and saves it to a repository (read snapshot for more information). The backup process requires a repository to be created first. The repository needs to be registered using the _snapshot endpoint, and multiple repositories can be created per cluster. The following repository types are supported:
Repository types
| Repository type | Configuration type |
|---|---|
| Shared file system | Type: “fs” |
| S3 | Type : “s3” |
| HDFS | Type :“hdfs” |
| Azure | Type: “azure” |
| Google Cloud Storage | Type : “gcs” |
Examples
To register an “fs” repository:
PUT _snapshot/my_repo_01
{
"type": "fs",
"settings": {
"location": "/mnt/my_repo_dir"
}
}Notes and good things to know
- S3, HDFS, Azure and Google Cloud require a relevant plugin to be installed before it can be used for a snapshot.
- The setting, path.repo: /mnt/my_repo_dir needs to be added to elasticsearch.yml on all the nodes if you are planning to use the repo type of file system. Otherwise, it will fail.
- When using remote repositories, the network bandwidth and repository storage throughput should be high enough to complete the snapshot operations normally, otherwise you will end up with partial snapshots.
Log Context
Log “[{}] [{}] failed to list directory – some of files might not be deleted” classname is FileRestoreContext.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :
} catch (IOException e) {
logger.warn("[{}] [{}] failed to delete file [{}] during snapshot cleanup"; shardId; snapshotId; storeFile);
}
}
} catch (IOException e) {
logger.warn("[{}] [{}] failed to list directory - some of files might not be deleted"; shardId; snapshotId);
}
}
/**
* Restores given list of {@link BlobStoreIndexShardSnapshot.FileInfo} to the given {@link Store}.
