Check data distribution between storage devices in Aiven for ClickHouse®’s tiered storage#


Aiven for ClickHouse® tiered storage is a limited availability feature. If you’re interested in trying out this feature, contact the sales team at

Monitor how your data is distributed between the two layers of your tiered storage: SSD and object storage.

About checking data distribution#

If you have the tiered storage feature enabled on your project, your data in Aiven for ClickHouse is distributed between two storage devices (tiers). You can check on what storage devices your databases and tables are stored. You can also preview their total sizes as well as part counts, minimum part sizes, median part sizes, and maximum part sizes.


Check data distribution in Aiven Console#

You can use Aiven Console to check if tiered storage is enabled on your service and, if it is, how much storage is used on each tier (local SSD and remote object storage) for particular tables.

To access tiered storage’s status information, go to Aiven Console > your Aiven for ClickHouse service > the Databases and tables page > your database > your table > View details > Storage details.

Run a data distribution check with the ClickHouse client (CLI)#

  1. Connect to your Aiven for ClickHouse service using, for example, the ClickHouse client (CLI).

  2. Run the following query:

        formatReadableSize(sum(data_compressed_bytes)) AS total_size,
        count(*) AS parts_count,
        formatReadableSize(min(data_compressed_bytes)) AS min_part_size,
        formatReadableSize(median(data_compressed_bytes)) AS median_part_size,
        formatReadableSize(max(data_compressed_bytes)) AS max_part_size
        database ASC,
        table ASC,
        disk_name ASC

    You can expect to receive the following output:

    │ datasets  hits_v1    default    1.20 GiB              6  33.65 MiB      238.69 MiB        253.18 MiB    │
    │ datasets  visits_v1  S3         536.69 MiB            5  44.61 MiB      57.90 MiB         317.19 MiB    │
    │ system    query_log  default    75.85 MiB           102  7.51 KiB       12.36 KiB         1.55 MiB      │


The query returns a table with data distribution details for all databases and tables that belong to your service: the storage device they use, their total sizes as well as parts counts and sizing.

What’s next#