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* prefer relative links from root * wip * split aggregate function reference * split system tables
27 lines
2.1 KiB
Markdown
27 lines
2.1 KiB
Markdown
# system.disks {#system_tables-disks}
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Contains information about disks 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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- `name` ([String](../../sql-reference/data-types/string.md)) — Name of a disk in the server configuration.
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- `path` ([String](../../sql-reference/data-types/string.md)) — Path to the mount point in the file system.
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- `free_space` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Free space on disk in bytes.
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- `total_space` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Disk volume in bytes.
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- `keep_free_space` ([UInt64](../../sql-reference/data-types/int-uint.md)) — Amount of disk space that should stay free on disk in bytes. Defined in the `keep_free_space_bytes` parameter of disk configuration.
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## 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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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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