Could not read repository data from index blob – How to solve this Elasticsearch exception

Opster Team

August-23, Version: 6.8-8.9

Briefly, this error occurs when Elasticsearch fails to read the repository data from the index blob. This could be due to corruption of the blob, insufficient permissions, or connectivity issues with the storage backend. To resolve this, you can try the following: 1) Check and correct the permissions of the blob storage. 2) Verify the connectivity with the storage backend. 3) If the blob is corrupted, restore it from a backup. 4) If the issue persists, consider reindexing the data.

This guide will help you check for common problems that cause the log ” could not read repository data from index blob ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: blobstore, repository, index, repositories.

Log Context

Log “could not read repository data from index blob” class name is We extracted the following from Elasticsearch source code for those seeking an in-depth context :

 // operations must start from the EMPTY_REPO_GEN again
 if (latestKnownRepoGen.compareAndSet(indexGen; RepositoryData.EMPTY_REPO_GEN)) {
 logger.warn("Resetting repository generation tracker because we failed to read generation [" + indexGen + "]"; ioe);
 throw new RepositoryException(; "could not read repository data from index blob"; ioe);
 }  private static String testBlobPrefix(String seed) {
 return TESTS_FILE + seed;