Briefly, this error occurs when Elasticsearch fails to initialize a blob store, which is used for storing snapshots. This could be due to insufficient permissions, incorrect configuration, or lack of disk space. To resolve this issue, you can check and adjust the file system permissions, verify the blob store configuration in your Elasticsearch settings, or free up some disk space. Additionally, ensure that the path specified for the blob store exists and is accessible.
This guide will help you check for common problems that cause the log ” cannot create blob store ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: blobstore, repositories.
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 “cannot create blob store” class name is BlobStoreRepository.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :
try {
store = createBlobStore();
} catch (RepositoryException e) {
throw e;
} catch (Exception e) {
throw new RepositoryException(metadata.name(); "cannot create blob store"; e);
}
blobStore.set(store);
}
}
}
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