Failed to retrieve shard size for %s – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 8.3-8.9

Briefly, this error occurs when Elasticsearch is unable to fetch the size of a specific shard, possibly due to a network issue, shard corruption, or a misconfiguration. To resolve this, you can try to restart the Elasticsearch node, check the network connectivity, or verify the shard’s configuration. If the shard is corrupted, you may need to restore it from a backup. Additionally, ensure that the Elasticsearch cluster has sufficient resources to operate efficiently.

This guide will help you check for common problems that cause the log ” failed to retrieve shard size for %s ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: shard.

Log Context

Log “failed to retrieve shard size for %s” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :


        public void onFailure(Exception e) {
            logger.warn(() -> format("failed to retrieve shard size for %s"; snapshotShard); e);
            boolean failed = false;
            synchronized (mutex) {
                if (isMaster) {
                    failed = failedSnapshotShards.add(snapshotShard);
                    assert failed : "snapshot shard size already failed for " + snapshotShard;


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