Briefly, this error occurs when Elasticsearch is unable to convert the repository data into a format that can be stored or transferred. This could be due to a variety of reasons such as incompatible data types, incorrect data format, or a bug in the serialization process. To resolve this issue, you can try the following: 1) Check the data types and formats to ensure they are compatible with Elasticsearch. 2) Update Elasticsearch to the latest version to fix any potential bugs. 3) If the error persists, consider reindexing your data or using a different repository.
This guide will help you check for common problems that cause the log ” Failed to serialize repository data ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: repositories, blobstore, repository.
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 serialize repository data” classname is BlobStoreRepository.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :
return null;
}
return serialized;
} catch (IOException e) {
assert false : new AssertionError("Impossible; no IO happens here"; e);
logger.warn("Failed to serialize repository data"; e);
return null;
}
}
private RepositoryException corruptedStateException(@Nullable Exception cause; @Nullable Tuple previousWriterInfo) {
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