Final answer:
Splunk's clustered buckets include a GUID in their naming convention to distinguish them from non-clustered buckets, which do not require such identifiers as they aren't part of a replication factor within a cluster.
Step-by-step explanation:
In Splunk's bucket naming convention, clustered buckets are distinguished from non-clustered buckets by a specific naming element that denotes whether the bucket is part of a cluster. Clustered buckets will have a GUID (Globally Unique Identifier) appended to their names, which is a long string of characters that identifies the bucket uniquely across the cluster. This allows Splunk to manage replication and search factor across multiple indexers. On the other hand, non-clustered buckets do not contain a GUID because they do not need to be identified across multiple systems within a cluster.