AxonOps Data Dashboard Metrics Mapping¶

This document maps the metrics used in the AxonOps Data dashboard.

Dashboard Overview¶

The Data dashboard provides insights into data storage characteristics including compression ratios, disk space usage, SSTable counts, and partition sizes. It helps monitor data distribution and identify tables with potential issues like large partitions or poor compression.

Metrics Mapping¶

Compression Metrics¶

Dashboard Metric	Description	Attributes
`cas_Table_CompressionRatio`	Compression effectiveness ratio	`keyspace`, `scope` (table), `dc`, `rack`, `host_id`
`cas_Table_CompressionMetadataOffHeapMemoryUsed`	Off-heap memory used by compression metadata	`keyspace`, `scope` (table), `dc`, `rack`, `host_id`

Disk Space Metrics¶

Dashboard Metric	Description	Attributes
`cas_Table_LiveDiskSpaceUsed`	Live data disk space (excludes deleted data)	`keyspace`, `scope` (table), `function=Count`, `dc`, `rack`, `host_id`
`cas_Table_TotalDiskSpaceUsed`	Total disk space including tombstones	`keyspace`, `scope` (table), `function=Count`, `dc`, `rack`, `host_id`
`cas_Table_LiveSSTableCount`	Number of live SSTables	`keyspace`, `scope` (table), `dc`, `rack`, `host_id`

Partition Size Metrics¶

Dashboard Metric	Description	Attributes
`cas_Table_MinPartitionSize`	Minimum partition size in bytes	`keyspace`, `scope` (table), `dc`, `rack`, `host_id`
`cas_Table_MeanPartitionSize`	Average partition size in bytes	`keyspace`, `scope` (table), `dc`, `rack`, `host_id`
`cas_Table_MaxPartitionSize`	Maximum partition size in bytes	`keyspace`, `scope` (table), `dc`, `rack`, `host_id`

Query Examples¶

Compression Ratio¶

cas_Table_CompressionRatio{scope=~'$scope', scope!='', dc=~'$dc',rack=~'$rack',host_id=~'$host_id',keyspace=~'$keyspace'}

Compression Metadata Memory¶

cas_Table_CompressionMetadataOffHeapMemoryUsed{scope=~'$scope', scope!='', dc=~'$dc',rack=~'$rack',host_id=~'$host_id',keyspace=~'$keyspace'}

Live Disk Space Per Table¶

cas_Table_LiveDiskSpaceUsed{function='Count',dc=~'$dc',rack=~'$rack',host_id=~'$host_id',keyspace=~'$keyspace',scope=~'$scope', scope!=''}

Total Disk Space Per Table¶

cas_Table_TotalDiskSpaceUsed{function='Count',dc=~'$dc',rack=~'$rack',host_id=~'$host_id',keyspace=~'$keyspace',scope=~'$scope'}

SSTable Count¶

cas_Table_LiveSSTableCount{dc=~'$dc',rack=~'$rack',host_id=~'$host_id',scope=~'$scope', scope!=''}

Partition Size Metrics¶

// Minimum
cas_Table_MinPartitionSize{dc=~'$dc',rack=~'$rack',host_id=~'$host_id',scope=~'$scope', scope!=''}

// Mean
cas_Table_MeanPartitionSize{dc=~'$dc',rack=~'$rack',host_id=~'$host_id',scope=~'$scope', scope!=''}

// Maximum
cas_Table_MaxPartitionSize{dc=~'$dc',rack=~'$rack',host_id=~'$host_id',scope=~'$scope', scope!=''}

Panel Organization¶

Compression Section¶

Compression Ratio - Line chart showing compression effectiveness (lower is better)
Compression Metadata Off-Heap Memory per Table - Memory overhead of compression

Disk Space Per Node Section¶

Live Disk Space Per Table - Active data size per table
Total Disk Space Per Table - Total size including tombstones
Live SSTable Count Per Table - Number of SSTables per table

Row Size Per Node Section¶

Min Partition Size Per Table - Smallest partition in each table
Mean Partition Size Per Table - Average partition size
Max Row Size Per Table - Largest partition (identifies potential hotspots)

Filters¶

data center (dc) - Filter by data center
rack - Filter by rack
node (host_id) - Filter by specific node
keyspace - Filter by keyspace
table (scope) - Filter by table

Important Metrics Explained¶

Compression Ratio¶

Shows how well data compresses
Lower values mean better compression
Typical values: 0.3-0.5 for text data
Depends on compression algorithm and data type

Disk Space Metrics¶

Live Space: Only counts active data
Total Space: Includes tombstones and deleted data
Difference indicates space that can be reclaimed by compaction

SSTable Count¶

High counts may indicate:
- Need for compaction tuning
- High write load
- Compaction falling behind
Affects read performance (more SSTables = more files to check)

Partition Size Distribution¶

Min Size: Usually very small (empty or near-empty partitions)
Mean Size: Average across all partitions
Max Size: Critical for identifying large partitions
Partitions > 100MB can cause performance issues
Partitions > 1GB should be investigated

Legend Format¶

All panels use: $dc - $host_id-$keyspace-$scope

Shows data center, node, keyspace, and table
Allows easy identification of specific table metrics

Best Practices¶

Monitor Compression Ratio:

Sudden changes may indicate data pattern changes
Poor compression might suggest wrong algorithm choice

Watch Disk Space Growth:

Compare live vs total space
Large differences suggest need for compaction

Track SSTable Counts:

Consistently high counts impact read performance
May need to adjust compaction strategy

Monitor Partition Sizes:

Large partitions (>100MB) need investigation
Very large partitions (>1GB) can cause operational issues
Consider data model changes for tables with large partitions

Notes¶

The scope!='' filter excludes empty table names
function='Count' is used for disk space metrics
All size metrics use binary units (bytes, not SI units)
Partition size metrics are estimates based on sampling