Redis Flex and Auto Tiering Metrics

The following additional metrics for Redis Flex and Auto Tiering databases are available in the Redis Enterprise Cluster Manager UI.

% Values in RAM

Percent of keys whose values are stored in RAM.

A low percentage alert means most of the RAM is used for holding keys and not much RAM is available for values. This can be due to a high number of small keys or a few large keys. Inserting more keys might cause the database to run out of memory.

If the percent of values in RAM is low for a subset of the database's shards, it might also indicate an unbalanced database.

Components measured: Database and Shard

Values in flash

Number of keys with values stored in flash, not including replication.

Components measured: Database and Shard

Values in RAM

Number of keys with values stored in RAM, not including replication.

Components measured: Database and Shard

Flash key-value operations

Number of operations on flash key values (read + write + del) per second.

Components measured: Node

Flash bytes/sec

Number of total bytes read and written per second on flash memory.

Components measured: Cluster, Node, Database, and Shard

Flash I/O operations/sec

Number of input/output operations per second on the flash storage device.

Components measured: Cluster and Node

RAM:Flash access ratio

Ratio between logical Redis key value operations and actual flash key value operations.

Components measured: Database and Shard

RAM hit ratio

Ratio of requests processed directly from RAM to total number of requests processed.

Components measured: Database and Shard

Used flash

Total amount of memory used to store values in flash.

Components measured: Database and Shard

Free flash

Amount of free space on flash storage.

Components measured: Cluster and Node

Flash fragmentation

Ratio between the used logical flash memory and the physical flash memory that is used.

Components measured: Database and Shard

Used RAM

Total size of data stored in RAM, including keys, values, overheads, and replication (if enabled).

Components measured: Database and Shard

RAM dataset overhead

Percentage of the RAM limit that is used for anything other than values, such as key names, dictionaries, and other overheads.

Components measured: Database and Shard

RAM limit

Maximum amount of RAM that can be used in bytes.

Components measured: Database

RAM usage

Percentage of the RAM limit used.

Components measured: Database

Storage engine usage

Total count of shards used, filtered by the sorage engine (Speedb / RockSB) per given database.

Components measured: Database, Shards

Calculated metrics

These RoF statistics can be calculated from other metrics.

• RoF average key size with overhead

  (ram_dataset_overhead * used_ram) / (total_keys * 2)

• RoF average value size in RAM

  ((1 - ram_dataset_overhead) * used_ram) / (values_in_ram * 2)

• RoF average value size in flash

  used_flash / values_in_flash