Determined repository generation – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 7.5-7.11

Briefly, this error occurs when Elasticsearch encounters an issue with the snapshot repository, specifically with the generation number. The generation number is a unique identifier for each snapshot. This error can be caused by a mismatch between the expected and actual generation number. To resolve this issue, you can try the following: 1) Verify the repository and its settings, 2) Check the snapshot status and delete any corrupted or incomplete snapshots, 3) If the issue persists, consider creating a new repository and moving the snapshots there.

This guide will help you check for common problems that cause the log ” Determined repository generation [ ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: repository, repositories, blobstore.

Log Context

Log “Determined repository generation [” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

                        new RepositoryException(; "Could not determine repository generation from root blobs"; e));
                genToLoad = latestKnownRepoGen.updateAndGet(known -> Math.max(known; generation));
                if (genToLoad > generation) {
          "Determined repository generation [" + generation
                        + "] from repository contents but correct generation must be at least [" + genToLoad + "]");
            } else {
                // We only rely on the generation tracked in #latestKnownRepoGen which is exclusively updated from the cluster state
                genToLoad = latestKnownRepoGen.get();