SSD and HDD tiered storage

You can set parameters for dynamic partitions across different disk types, facilitating data migration from SSDs to HDDs based on the hot and cold characteristics of the data. This strategy improves read and write performance in Doris while lowering costs.

For parameters of dynamic partitions, please refer to [Data Partitioning - Dynamic Partitioning](/docs/table-design/data-partition#Dynamic partitioning).

• dynamic_partition.hot_partition_num

  Doris supports data migration between different disk types (HDD, SSD) based on the cold/hot characteristics of the data, which can accelerate read and write performance. Users can set partition parameters to create dynamic partitions on the corresponding disk types.

  For the 'dynamic_partition' parameter, please refer to data-partition."

:::tip

If there is no SSD disk path under the storage path, configuring this parameter will cause dynamic partition creation to fail.

:::

hot_partition_num is all partitions in the previous n days and in the future.

Let us give an example. Suppose today is 2021-05-20, partition by day, and the properties of dynamic partition are set to: hot_partition_num=2, end=3, start=-3. Then the system will automatically create the following partitions, and set the storage_medium and storage_cooldown_time properties:

p20210517: ["2021-05-17", "2021-05-18") storage_medium=HDD storage_cooldown_time=9999-12-31 23:59:59
p20210518: ["2021-05-18", "2021-05-19") storage_medium=HDD storage_cooldown_time=9999-12-31 23:59:59
p20210519: ["2021-05-19", "2021-05-20") storage_medium=SSD storage_cooldown_time=2021-05-21 00:00:00
p20210520: ["2021-05-20", "2021-05-21") storage_medium=SSD storage_cooldown_time=2021-05-22 00:00:00
p20210521: ["2021-05-21", "2021-05-22") storage_medium=SSD storage_cooldown_time=2021-05-23 00:00:00
p20210522: ["2021-05-22", "2021-05-23") storage_medium=SSD storage_cooldown_time=2021-05-24 00:00:00
p20210523: ["2021-05-23", "2021-05-24") storage_medium=SSD storage_cooldown_time=2021-05-25 00:00:00

• dynamic_partition.storage_medium

  Note

  This parameteres is supported since Doris version 1.2.3

  Specifies the default storage medium for the created dynamic partition. HDD is the default, SSD can be selected.

  Note that when set to SSD, the hot_partition_num property will no longer take effect, all partitions will default to SSD storage media and the cooldown time will be 9999-12-31 23:59:59.