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Updated: Jan-20
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Troubleshooting Background
Related Issues
Log Context
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Troubleshooting background
To troubleshoot Elasticsearch log “Cannot read snapshot file” it’s important to understand common problems related to Elasticsearch concepts: blobstore, discovery-file, repositories, repository-azure, snapshot. See detailed explanations below complete with common problems, examples and useful tips.
Repository in Elasticsearch
What it is
An Elasticsearch snapshot provides a backup mechanism that takes the current state and data in the cluster and saves it to a repository (read the Glossary term 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 per cluster can be created. 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 a repository of type fs:
PUT _snapshot/my_repo_01
{
"type": "fs",
"settings": {
"location": "/mnt/my_repo_dir"
}
}
Notes and common problems
- S3, HDFS , Azure and Google Cloud requires 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 in case you are planning to use repo type of file system otherwise it will fail
- In case of 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 in partial snapshots.
Related issues to this log
To help troubleshoot related issues we have gathered selected Q&A from the community and issues from Github , please review the following for further information :
Log Context
Log ”Cannot read snapshot file [{}]” classname is BlobStoreRepository.java
We have extracted the following from Elasticsearch source code to get an in-depth context :
try {
snapshot = getSnapshotInfo(snapshotId);
} catch (SnapshotMissingException ex) {
throw ex;
} catch (IllegalStateException | SnapshotException | ElasticsearchParseException ex) {
logger.warn(() -> new ParameterizedMessage("cannot read snapshot file [{}]"; snapshotId); ex);
}
try {
// Delete snapshot from the index file; since it is the maintainer of truth of active snapshots
final RepositoryData updatedRepositoryData = repositoryData.removeSnapshot(snapshotId);
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