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2.4 KiB
2.4 KiB
slug |
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/en/operations/system-tables/storage_policies |
storage_policies
Contains information about storage policies and volumes defined in the server configuration.
Columns:
policy_name
(String) — Name of the storage policy.volume_name
(String) — Volume name defined in the storage policy.volume_priority
(UInt64) — Volume order number in the configuration, the data fills the volumes according this priority, i.e. data during inserts and merges is written to volumes with a lower priority (taking into account other rules: TTL,max_data_part_size
,move_factor
).disks
(Array(String)) — Disk names, defined in the storage policy.volume_type
(Enum8) — Type of volume. Can have one of the following values:JBOD
SINGLE_DISK
UNKNOWN
max_data_part_size
(UInt64) — Maximum size of a data part that can be stored on volume disks (0 — no limit).move_factor
(Float64) — 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.prefer_not_to_merge
(UInt8) — Value of theprefer_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.perform_ttl_move_on_insert
(UInt8) — Value of theperform_ttl_move_on_insert
setting. — Disables TTL move on data part INSERT. By default if we insert a data part that already expired by the TTL move rule it immediately goes to a volume/disk declared in move rule. This can significantly slowdown insert in case if destination volume/disk is slow (e.g. S3).load_balancing
(Enum8) — Policy for disk balancing. Can have one of the following values:ROUND_ROBIN
LEAST_USED
If the storage policy contains more then one volume, then information for each volume is stored in the individual row of the table.