Tiered storage performance metrics 

Storage tier metrics allow drilling down into specific storage tiers for a table to monitor the data distribution.

Storage tier metrics allow drilling down into specific storage tiers for a table to monitor the data distribution.

To view a storage metric, a table and tier number must be specified. DSE identifies tiers by number. Zero represents the tier with the newest data. The number increases by one for each older tier.
Note: An additional implicit tier exists that represents the oldest data. For instance, if max_tier_ages for a table is set to 60,120, there are three tiers: Tier 0 would be for data newer than 60 seconds, tier 1 would be for data between 60 seconds and 120 seconds, and tier 2 would be for data older than 120 seconds.

For more information, see DSE Tiered Storage.

TIER: Max Data Age
Timestamp in local server time that represents an upper bound to the newest piece of data stored in the SSTable. When a new SSTable is flushed, it is set to the time of creation. When an SSTable is created from compaction, it is set to the max of all merged SSTables.
TIER: sstables
Number of SSTables in a tier for a table.
TIER: Total Disk Used
Disk space used by a table by SSTables for the tier.