NodeSync metric MBeans
The NodeSync MBeans track the data validation operations on a node.
Using DataStax Enterprise (DSE) OpsCenter 6.5 or 6.7 to monitor these metrics in alerts and dashboard graphs.
Use the following syntax to locate and use NodeSync MBeans:
-
Global metric name syntax:
com.datastax.nodesync:type=NodeSyncMetrics,name=metric_name -
Per table metric name syntax:
org.apache.cassandra.metrics:type=Table,keyspace=keyspace_name,scope=table_name,name=metric_name
The following screen shows the Global MBeans using jconsole:
NodeSync metrics
Object metrics
NodeSync repairs data and objects, the latter of which can be rows, range tombstones, and deletion information.
- NodeSyncObjectsRepaired
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Inconsistent objects (rows + range tombstones) that NodeSync validated and repaired. The number of rows and range tombstones is equivalent to
NodeSyncDataRepaired. - NodeSyncObjectsValidated
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Number of objects (rows + range tombstones) that NodeSync validated by checking for inconsistencies. The number of rows and range tombstones is equivalent to
NodeSyncDataValidated. - NodeSyncRepairObjectsSent
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Number of objects sent required to repair replicas. This attribute differs from
NodeSyncDataRepairedin that 100 bytes of data that was inconsistent and repaired can be sent to multiple replicas, providing a more accurate representation of repair traffic generated between nodes.
Data metrics
- NodeSyncDataValidated
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Amount of data (in bytes) that NodeSync validated by checking for inconsistencies.
- NodeSyncDataRepaired
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Inconsistent data that NodeSync validated and repaired.
- NodeSyncRepairDataSent
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Size of data (in bytes) sent for repairing inconsistencies found by NodeSync. This metric differs from
NodeSyncDataRepairedin that if a row of a specific size is inconsistent, that number is counted inNodeSyncDataRepaired. However, more or less of the same number can be counted inNodeSyncRepairDataSent, because the row can be inconsistent on more than one node, but only a portion of the row might be inconsistent (and thus sent).
Page metrics
NodeSync validates data by pages, which are the least granular objects that NodeSync operates on. NodeSync collects pages by outcomes, and the resulting numbers are meaningful in comparison. For example, the percentage of pages already fully in sync that did not require repair.
- NodeSyncFailedPages
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Number of pages not validated due to an unexpected error.
- NodeSyncFullInSyncPages
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Number of pages fully validated (all replicas responded) that had no inconsistencies.
- NodeSyncFullRepairedPages
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Number of pages fully validated (all replicas responded) that had inconsistencies, and which were successfully repaired.
- NodeSyncPartialInSyncPages
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Number of pages partially validated (some replicas responded) that had no inconsistencies.
- NodeSyncPartialRepairedPages
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Number of pages partially validated (some replicas responded) that had inconsistencies, and which were successfully repaired.
- NodeSyncProcessedPages
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Total number of processed pages since the last node restart, calculated as the sum of all other page counters.
- NodeSyncUncompletedPages
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Subset of
NodeSyncProcessedPagesthat failed to process. The reason could be that only one node was up and the page was skipped, some replicas failed during processing, or some unexpected error occurred.
NodeSync MBean attributes
Each of the following metrics can return some or all of the NodeSync MBean attributes.
- MeanRate
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Mean of the OneMinuteRate, FiveMinuteRate, and FifteenMinuteRate attributes.
- OneMinuteRate
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Number of objects processed for the given MBean in a one minute period.
- FiveMinuteRate
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Number of objects processed for the given MBean in a five minute period.
- FifteenMinuteRate
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Number of objects processed for the given MBean in a fifteen minute period.
- RateUnit
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Unit of measurement for rate processing, which is number of events per second.
- Count
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Total number of objects processed for the given MBean.
Example
To return the global mean rate of the node:
nodetool sjk mx -b "com.datastax.nodesync:type=NodeSyncMetrics,name=NodeSyncObjectsValidated" -f MeanRate -mgThe results show the object name and value.
com.datastax.nodesync:type=NodeSyncMetrics,name=NodeSyncObjectsValidated
2.542410005904823