Could not determine repository generation from root blobs – How to solve this Elasticsearch error

Opster Team

July-20, Version: 1.7-8.0

Before you begin reading this guide, we recommend you try running the Elasticsearch Error Check-Up which analyzes 2 JSON files to detect many configuration errors.

Briefly, this error occurs when Elasticsearch is unable to determine the repository generation from the root blobs in the repository. This could be due to issues with the repository or issues with the metadata stored in the repository. You will need to resolve the issue to create a successful snapshot.

To easily locate the root cause and resolve this issue try AutoOps for Elasticsearch & OpenSearch. It diagnoses problems by analyzing hundreds of metrics collected by a lightweight agent and offers guidance for resolving them.

This guide will help you check for common problems that cause the log ” Could not determine repository generation from root blobs ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: repositories, repository and blobstore.

Log Context

Log “Could not determine repository generation from root blobs”classname  is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

final long generation;
 try {
 generation = latestIndexBlobId();
 } catch (IOException ioe) {
 new RepositoryException(; "Could not determine repository generation from root blobs"; ioe));
 genToLoad = latestKnownRepoGen.updateAndGet(known -> Math.max(known; generation));
 if (genToLoad > generation) {"Determined repository generation [" + generation


See how you can use AutoOps to resolve issues

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