Updated: Jan-20
Elasticsearch Version: 1.7-8.0
Background
To resolve issues causing many log errors you can try our Elasticsearch Check-Up it analyses ES configuration to provide actionable recommendations (no installation required)
To troubleshoot log “Cannot read snapshot file” it’s important to understand a few problems related to Elasticsearch concepts blobstore, discovery-file, repositories, repository-azure, snapshot. See bellow important tips and explanations on these concepts
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.
Log Context
Log”Cannot read snapshot file [{}]” classname is BlobStoreRepository.java
We extracted the following from Elasticsearch source code for those seeking 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);
Related issues to this log
We have gathered selected Q&A from the community and issues from Github, that can help fix related issues please review the following for further information :
Cannot Read From Elasticsearch Usin
About Opster
Opster detects, resolves, optimizes, automates and prevents incidents in Elasticsearch. Opster’s line of products delivers a fundamentally more effective Elasticsearch operation and backs it up with superb production support and consulting.
