Monitoring Cluster Statistics
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You may have multiple SS embedded Cassandra clusters in multiple environments of your system. Please note that the cluster-config.xml file should be updated in one SS node of each Cassandra cluster.
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- Log in to the WSO2 Storage Server management console.
Go to the and Monitor menu and click Cassandra Stats. The Cluster Ring screen opens showing cluster-wide, keyspace-level and column-family-level statistics, such as gossip info, column family histograms etc.
The elements of this table are described below.Element Description Node Node IP State Current state of the node (Normal/Leaving/Joining/Moving) Data Center Data Center which this node belongs to Rack Rack which this node belongs to Status Current status of the node (Up/Down) Load Used disk storage Token Token of the node Ownership How much (%) data in the cluster is owned by this node Click Node to access its node-level statistics. The Node Stats screen opens as follows:
Different types of statistics on the cluster node can be accessed by clicking on each of the following links:
- Node Info
- Node InfoCF Stats
- Version
- Thread Pool Stats
- Compaction Stats
- Gossip Info
- Network StatsÂ
- Range KeyÂ
- Keyspace Stats
Node Info
An example of the Node Info screen is shows below.
The following table describes information shown in the above window.
General Properties:
| Element | Description |
|---|---|
| Token | Token of the node |
| GossipState | Gossip is enabled or not |
| Load | Used disk storage |
| Generation No | Times started |
| Up time(Seconds) | Server up time |
| Head Memory Usage(MB) | Head Memory Usage (MB) |
| Data center | Data Center which this node belongs to |
| Rack | Rack which this node belongs to |
| Exception Count | Exception Count |
CF Stats
Shows the column family information. For example,
The following table describes information shown in the above window.
Keyspace Information:
| Element | Description |
| Read Count | Number of read requests received since server startup |
| Read Latency(ms) | total time spent for read requests since server started divided by number of read requests since server started |
| Write Count | Number of write requests received since server startup |
| Write Latency (ms) | total time spent for write requests since server started divided by number of write requests since server started |
| Pending Tasks | Tasks in the queue for reads, writes, and cluster operations of tables in the keyspace. |
Column Family Information:
| Element | Description |
| SS Table Count | Number of SSTables containing data from the table |
| Space Used(live) | Total size of all live SS tables |
| Space Used(total) | Total size of all SS tables |
| Number of Keys (estimate) | NUmber of keys in the node |
| Memtable Column Count | Column Count in Memtable |
| Memtable Data Size | Data Size in Memtable |
| Memtable Switch Count | How many times a "full" memtable was swapped for an empty one |
| Read Count | Number of read requests received since server startup |
| Read Latency(ms) | total time spent for read requests since last call to jmx mbean divided by number of read requests since last call to jmx mbean |
| Write Count | Number of write requests received since server startup |
| Write Latency(ms) | total time spent for write requests since last call to jmx mbean divided by number of write requests since last call to jmx mbean |
| Pending Tasks | Approximate number of pending tasks thread pool has. |
| Bloom Filter False Positives | Number of false positives, which occur when the bloom filter said the row existed, but it actually did not exist in absolute numbers |
| Bloom Filter False Ratio | Fraction of all bloom filter checks resulting in a false positive |
| Bloom Filter Space Used | Bytes of bloom filter data |
| Compacted Row Minimum Size | Lower size limit in MB for table rows being compacted in memory |
| Compacted Row Maximum Size | Upper size limit in bytes for compacted table rows, configurable in the cassandra.yaml (in_memory_compaction _limit_in_mb) |
| Compacted Row Mean Size | The average size in bytes of compacted table rows |
Version
Shows the Cassandra Server version in a pop-up dialog box as follows:
Thread Pool Stats
Shows the thread pool statistics available for a node. Given below are descriptions of the information shown under general and dropped properties.
| Element | Description |
|---|---|
| ReadStage | Â |
| RequestResponseStage | Â |
| ReadRepairStage | Â |
| MutationStage | Â |
| ReplicateOnWriteStage | Â |
| GossipStage | Â |
| AntiEntropyStage | Â |
| MigrationStage | Â |
| StreamStage | Â |
| MemtablePostFlusher | Â |
| FlushWriter | Â |
| MiscStage | Â |
| commitlog_archiver | Â |
| InternalResponseStage | Â |
| HintedHandoff | Â |
| Message Type | Description |
|---|---|
| RANGE_SLICE | Â |
| READ_REPAIR | Â |
| BINARY | Â |
| READ | Â |
| MUTATION | Â |
| REQUEST_RESPONSE | Â |
Compaction StatsÂ
Shows the compaction statistics of the node as shown in the following example.
| Element | Description |
| Pending Tasks | How many pending compaction tasks are pending |
| Active Remaining Time | How much time remaining to complete compact tasks |
Gossip InfoÂ
Shows statistics of the Gossip server as shown in the following example.
Network StatsÂ
Range Key
Click Keyspace Stats in the Node Stats screen to view statistics of the key spaces and associated column families.
Keyspace Statistics
Shows the available keyspaces with operations as depicted in the example below.
It shows the following statistics for each keyspace.
| Operation | Description |
|---|---|
| Ownership | Â |
| Describe Ring | Â |
Click on a selected keyspace to view its column-family statistics.
Column Family Statistics
Click on the selected keyspace to open the column family statistics associated with it. The Column Family Stats screen opens. For example,
The table below gives information of each type of statistical data that can be viewed by clicking on each link on the screen.
| Stats Type | Description |
|---|---|
| Histogram | Â |
| Endpoints | Shows which node has a given key |
| SSTables | Shows which SS table has a given key |
| Compaction Thresholds | Â |