content/operate/rs/references/metrics/auto-tiering.md
The following additional metrics for [Redis Flex and Auto Tiering ]({{< relref "/operate/rs/databases/flash" >}}) databases are available in the Redis Software Cluster Manager UI.
{{<image filename="images/rs/screenshots/metrics/flash-db-metrics.png" alt="The database metrics page.">}}
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
Number of keys with values stored in flash, not including [replication]({{< relref "/operate/rs/databases/durability-ha/replication" >}}).
Components measured: Database and Shard
Number of keys with values stored in RAM, not including [replication]({{< relref "/operate/rs/databases/durability-ha/replication" >}}).
Components measured: Database and Shard
Number of operations on flash key values (read + write + del) per second.
Components measured: Node
Number of total bytes read and written per second on flash memory.
Components measured: Cluster, Node, Database, and Shard
Number of input/output operations per second on the flash storage device.
Components measured: Cluster and Node
Ratio between logical Redis key value operations and actual flash key value operations.
Components measured: Database and Shard
Ratio of requests processed directly from RAM to total number of requests processed.
Components measured: Database and Shard
Total amount of memory used to store values in flash.
Components measured: Database and Shard
Amount of free space on flash storage.
Components measured: Cluster and Node
Ratio between the used logical flash memory and the physical flash memory that is used.
Components measured: Database and Shard
Total size of data stored in RAM, including keys, values, overheads, and [replication]({{< relref "/operate/rs/databases/durability-ha/replication" >}}) (if enabled).
Components measured: Database and Shard
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
Maximum amount of RAM that can be used in bytes.
Components measured: Database
Percentage of the RAM limit used.
Components measured: Database
Total count of shards used, filtered by the sorage engine (Speedb / RockSB) per given database.
Components measured: Database, Shards
These RoF statistics can be calculated from other metrics.
RoF average key size with overhead
(ram_dataset_overhead * used_ram) / ([total_keys]({{< relref "/operate/rs/references/metrics/database-operations#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