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18 lines
1.6 KiB
Markdown
18 lines
1.6 KiB
Markdown
# system.storage_policies {#system_tables-storage_policies}
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Contains information about storage policies and volumes defined in the [server configuration](../../engines/table-engines/mergetree-family/mergetree.md#table_engine-mergetree-multiple-volumes_configure).
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Columns:
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- `policy_name` ([String](../../sql-reference/data-types/string.md)) — Name of the storage policy.
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- `volume_name` ([String](../../sql-reference/data-types/string.md)) — Volume name defined in the storage policy.
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- `volume_priority` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Volume order number in the configuration.
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- `disks` ([Array(String)](../../sql-reference/data-types/array.md)) — Disk names, defined in the storage policy.
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- `max_data_part_size` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Maximum size of a data part that can be stored on volume disks (0 — no limit).
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- `move_factor` ([Float64](../../sql-reference/data-types/float.md)) — Ratio of free disk space. When the ratio exceeds the value of configuration parameter, ClickHouse start to move data to the next volume in order.
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- `prefer_not_to_merge` ([UInt8](../../sql-reference/data-types/int-uint.md)) — Value of the `prefer_not_to_merge` setting. When this setting is enabled, merging data on this volume is not allowed. This allows controlling how ClickHouse works with slow disks.
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If the storage policy contains more then one volume, then information for each volume is stored in the individual row of the table.
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[Original article](https://clickhouse.tech/docs/en/operations/system_tables/storage_policies) <!--hide-->
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