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system.storage_policies

Description​

Contains information about storage policies and volumes which are defined in server configuration.

Columns​

  • policy_name (String) — The name of the storage policy.
  • volume_name (String) — The name of the volume.
  • volume_priority (UInt64) — The priority of the volume.
  • disks (Array(String)) — The list of all disks names which are a part of this storage policy.
  • volume_type (Enum8('JBOD' = 0, 'SINGLE_DISK' = 1, 'UNKNOWN' = 2)) — The type of the volume - JBOD or a single disk.
  • max_data_part_size (UInt64) — the maximum size of a part that can be stored on any of the volumes disks.
  • move_factor (Float32) — When the amount of available space gets lower than this factor, data automatically starts to move on the next volume if any (by default, 0.1).
  • prefer_not_to_merge (UInt8) — You should not use this setting. Disables merging of data parts on this volume (this is harmful and leads to performance degradation).
  • perform_ttl_move_on_insert (UInt8) — Disables TTL move on data part INSERT. By default (if enabled) 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.
  • load_balancing (Enum8('ROUND_ROBIN' = 0, 'LEAST_USED' = 1)) — Policy for disk balancing, round_robin or least_used.