Any errors associated with the sample. For example, if the aggregation of data over multiple nodes fails then any of the partial errors might be returned, “ok” on success, or “error” on any internal uncategorized failure. Whenever a sample collection is missed but done at a later time, it is back filled to the previous 15 second timestamp and tagged with "backfilled_data". “Inconsistent_ delta_time” is encountered when the time between two collections is not the same for all nodes. Therefore, the aggregated value might be over or under inflated. “Negative_delta” is returned when an expected monotonically increasing value has decreased in value. “Inconsistent_old_data” is returned when one or more nodes do not have the latest data.