Newts Monitoring

This section describes the metrics that Meridian collects to monitor the Newts keyspace from org.apache.cassandra.metrics.Keyspace on a Cassandra node.

JMX must be enabled on the Cassandra nodes and made accessible from Meridian to collect these metrics ( see Enabling JMX Authentication and Authorization in the Cassandra documentation).

The data collection process is bound to the agent IP interface whose service name is JMX-Cassandra-Newts. The JMXCollector retrieves MBean entities from the Cassandra node.

All memtables data size

Collected data size metrics for all memtables
Name	Description
AllMemtablesLiveDataSize	Total amount of live data stored in the memtables (2i and pending flush memtables included) that reside off heap, excluding any data structure overhead.
AllMemtablesOffHeapDataSize	Total amount of data stored in the memtables (2i and pending flush memtables included) that reside off heap.
AllMemtablesOnHeapDataSize	Total amount of data stored in the memtables (2i and pending flush memtables included) that reside on heap.

Memtable switch count

Collected memtable switch count metric
Name	Description
MemtableSwitchCount	Number of times flush has resulted in the memtable being switched out.

Memtable columns count

Collected metric for number of memtable columns
Name	Description
MemtableColumnsCount	Total number of columns present in the memtable.

Memtable data size

Collected memtable data size metrics
Name	Description
MemtableLiveDataSize	Total amount of live data stored in the memtable, excluding any data structure overhead.
MemtableOffHeapDataSize	Total amount of data stored in the memtable that resides off heap, including column-related overhead and partitions overwritten.
MemtableOnHeapDataSize	Total amount of data stored in the memtable that resides on-heap, including column-related overhead and partitions overwritten.

Read and write latency

Collected read and write latency metrics
Name	Description
ReadTotalLatency	Local read metrics
WriteTotalLatency	Local write metrics

Range latency

Collected rage latency metric
Name	Description
RangeLatency 99th Percentile	Local range slice metrics 99th percentile

Latency

Collected latency metrics
Name	Description
CasCommitTotalLatency	Time spent on Casandra commits since process start.
CasPrepareTotalLatency	Time spent on Casandra prepare events since process start.
CasProposeTotalLatency	Time spent on Casandra propose events since process start.

Bloom filter disk space

Collected bloom filter disk space metric
Name	Description
BloomFilterDiskSpaceUsed	Disk space that the bloom filter uses.

Bloom filter off-heap memory

Collected bloom filter off-heap memory metric
Name	Description
BloomFilterOffHeapMemoryUsed	Off-heap memory that the bloom filter uses.

Newts memory usage

Collected Newts memory usage metrics
Name	Description
CompressionMetadataOffHeapMemoryUsed	Off-heap memory that the compression metadata uses.
IndexSummaryOffHeapMemoryUsed	Off-heap memory that the index summary uses.

Pending operations

Collected metrics for pending operations
Name	Description
PendingCompactions	Estimated number of pending compactions for this column family.
PendingFlushes	Estimated number of pending flushes for this column family.

Disk space usage

Collected disk space usage metrics
Name	Description
TotalDiskSpaceUsed	Total disk space that the SSTables belonging to this column family use, including obsolete ones waiting to be garbage collected.
LiveDiskSpaceUsed	Disk space used by SSTables belonging to this column family.