> ## Documentation Index
> Fetch the complete documentation index at: https://clickhouse.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# min_free_* MergeTree table settings

> ClickHouse MergeTree table settings in the min_free_* generated group.

export const SettingsInfoBlock = ({type, default_value, changeable_without_restart}) => {
  return <div className="not-prose" style={{
    display: "flex",
    flexWrap: "wrap",
    alignItems: "baseline",
    columnGap: "0.5rem",
    rowGap: "0.125rem",
    margin: "0.375rem 0",
    fontSize: "0.8125rem",
    lineHeight: "1.125rem"
  }}>
      <div style={{
    fontWeight: 600,
    opacity: 0.72
  }}>Type</div>
      <div style={{
    overflowWrap: "anywhere"
  }}>{type}</div>
      <div style={{
    fontWeight: 600,
    opacity: 0.72,
    marginInlineStart: "0.5rem"
  }}>Default</div>
      <div style={{
    overflowWrap: "anywhere"
  }}>{default_value}</div>
      {changeable_without_restart && <div style={{
    fontWeight: 600,
    opacity: 0.72,
    marginInlineStart: "0.5rem"
  }}>
          Changeable without restart
        </div>}
      {changeable_without_restart && <div style={{
    overflowWrap: "anywhere"
  }}>
          {changeable_without_restart}
        </div>}
    </div>;
};

These settings are available in [system.merge\_tree\_settings](/docs/reference/system-tables/merge_tree_settings) and are autogenerated from ClickHouse source.

<h2 id="min_free_disk_bytes_to_perform_insert">
  min\_free\_disk\_bytes\_to\_perform\_insert
</h2>

<SettingsInfoBlock type="UInt64" default_value="0" />

The minimum number of bytes that should be free in disk space in order to
insert data. If the number of available free bytes is less than
`min_free_disk_bytes_to_perform_insert` then an exception is thrown and the
insert is not executed. Note that this setting:

* takes into account the `keep_free_space_bytes` setting.
* does not take into account the amount of data that will be written by the
  `INSERT` operation.
* is only checked if a positive (non-zero) number of bytes is specified

Possible values:

* Any positive integer.

<Note>
  If both `min_free_disk_bytes_to_perform_insert` and `min_free_disk_ratio_to_perform_insert`
  are specified, ClickHouse will count on the value that will allow to perform
  inserts on a bigger amount of free memory.
</Note>

<h2 id="min_free_disk_ratio_to_perform_insert">
  min\_free\_disk\_ratio\_to\_perform\_insert
</h2>

<SettingsInfoBlock type="Float" default_value="0" />

The minimum free to total disk space ratio to perform an `INSERT`. Must be a
floating point value between 0 and 1. Note that this setting:

* takes into account the `keep_free_space_bytes` setting.
* does not take into account the amount of data that will be written by the
  `INSERT` operation.
* is only checked if a positive (non-zero) ratio is specified

Possible values:

* Float, 0.0 - 1.0

Note that if both `min_free_disk_ratio_to_perform_insert` and
`min_free_disk_bytes_to_perform_insert` are specified, ClickHouse will count
on the value that will allow to perform inserts on a bigger amount of free
memory.