.. _rados_config_pool_pg_crush_ref:

====================================== Pool, PG and CRUSH Config Reference

.. index:: pools; configuration

The number of placement groups that the CRUSH algorithm assigns to each pool is determined by the values of variables in the centralized configuration database in the monitor cluster.

Both containerized deployments of Ceph (deployments made using cephadm or Rook) and non-containerized deployments of Ceph rely on the values in the central configuration database in the monitor cluster to assign placement groups to pools.

Example Commands

To see the value of the variable that governs the number of placement groups in a given pool, run a command of the following form:

.. prompt:: bash

ceph config get osd osd_pool_default_pg_num

To set the value of the variable that governs the number of placement groups in a given pool, run a command of the following form:

.. prompt:: bash

ceph config set osd osd_pool_default_pg_num

Manual Tuning

In some cases, it might be advisable to override some of the defaults. For example, you might determine that it is wise to set a pool's replica size and to override the default number of placement groups in the pool. You can set these values when running pool_ commands.

See Also

See :ref:pg-autoscaler.

.. literalinclude:: pool-pg.conf :language: ini

.. confval:: mon_max_pool_pg_num .. confval:: mon_pg_stuck_threshold .. confval:: mon_pg_warn_min_per_osd .. confval:: mon_pg_warn_min_objects .. confval:: mon_pg_warn_min_pool_objects .. confval:: mon_pg_check_down_all_threshold .. confval:: mon_pg_warn_max_object_skew .. confval:: mon_delta_reset_interval .. confval:: osd_crush_chooseleaf_type .. confval:: osd_crush_initial_weight .. confval:: osd_pool_default_crush_rule .. confval:: osd_pool_erasure_code_stripe_unit .. confval:: osd_pool_default_size .. confval:: osd_pool_default_min_size .. confval:: osd_pool_default_pg_num .. confval:: osd_pool_default_pgp_num .. confval:: osd_pool_default_pg_autoscale_mode .. confval:: osd_pool_default_flags .. confval:: osd_max_pgls .. confval:: osd_min_pg_log_entries .. confval:: osd_max_pg_log_entries .. confval:: osd_default_data_pool_replay_window .. confval:: osd_max_pg_per_osd_hard_ratio .. confval:: osd_pool_default_flag_ec_optimizations

.. _pool: ../../operations/pools .. _Monitoring OSDs and PGs: ../../operations/monitoring-osd-pg#peering .. _Weighting Bucket Items: ../../operations/crush-map#weightingbucketitems