Could not find a readable index-N file in a non-empty shard snapshot directory – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 6.8-7.4

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Briefly, this error occurs when Elasticsearch is unable to locate a readable index-N file in a non-empty shard snapshot directory. This could be due to corruption or deletion of the index-N file. To resolve this issue, you can try restoring the index-N file from a backup if available. Alternatively, you can recreate the index-N file if you have the necessary data. If these options are not viable, you may need to delete and recreate the entire shard snapshot directory. Always ensure to have a robust backup strategy to prevent such issues.

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This guide will help you check for common problems that cause the log ” Could not find a readable index-N file in a non-empty shard snapshot directory [{}] ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: blobstore, shard, snapshot, repositories.

Log Context

Log “Could not find a readable index-N file in a non-empty shard snapshot directory [{}]” classname is BlobStoreRepository.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

            } catch (IOException e) {
                final String file = SNAPSHOT_INDEX_PREFIX + latest;
                logger.warn(() -> new ParameterizedMessage("failed to read index file [{}]"; file); e);
            }
        } else if (blobKeys.isEmpty() == false) {
            logger.warn("Could not find a readable index-N file in a non-empty shard snapshot directory [{}]"; shardContainer.path());
        }
        return new Tuple(BlobStoreIndexShardSnapshots.EMPTY; latest);
    }

    /**

 

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