====================================== Pool, PG and CRUSH Config Reference ====================================== .. index:: pools; configuration When you create pools and set the number of placement groups (PGs) for each, Ceph uses default values when you don't specifically override the defaults. **We recommend** overriding some of the defaults. Specifically, we recommend setting a pool's replica size and overriding the default number of placement groups. You can specifically set these values when running `pool`_ commands. You can also override the defaults by adding new ones in the ``[global]`` section of your Ceph configuration file. .. literalinclude:: pool-pg.conf :language: ini ``mon_max_pool_pg_num`` :Description: The maximum number of placement groups per pool. :Type: Integer :Default: ``65536`` ``mon_pg_create_interval`` :Description: Number of seconds between PG creation in the same Ceph OSD Daemon. :Type: Float :Default: ``30.0`` ``mon_pg_stuck_threshold`` :Description: Number of seconds after which PGs can be considered as being stuck. :Type: 32-bit Integer :Default: ``300`` ``mon_pg_min_inactive`` :Description: Raise ``HEALTH_ERR`` if the count of PGs that have been inactive longer than the ``mon_pg_stuck_threshold`` exceeds this setting. A non-positive number means disabled, never go into ERR. :Type: Integer :Default: ``1`` ``mon_pg_warn_min_per_osd`` :Description: Raise ``HEALTH_WARN`` if the average number of PGs per ``in`` OSD is under this number. A non-positive number disables this. :Type: Integer :Default: ``30`` ``mon_pg_warn_min_objects`` :Description: Do not warn if the total number of RADOS objects in cluster is below this number :Type: Integer :Default: ``1000`` ``mon_pg_warn_min_pool_objects`` :Description: Do not warn on pools whose RADOS object count is below this number :Type: Integer :Default: ``1000`` ``mon_pg_check_down_all_threshold`` :Description: Percentage threshold of ``down`` OSDs above which we check all PGs for stale ones. :Type: Float :Default: ``0.5`` ``mon_pg_warn_max_object_skew`` :Description: Raise ``HEALTH_WARN`` if the average RADOS object count per PG of any pool is greater than ``mon_pg_warn_max_object_skew`` times the average RADOS object count per PG of all pools. Zero or a non-positive number disables this. Note that this option applies to ``ceph-mgr`` daemons. :Type: Float :Default: ``10`` ``mon_delta_reset_interval`` :Description: Seconds of inactivity before we reset the PG delta to 0. We keep track of the delta of the used space of each pool, so, for example, it would be easier for us to understand the progress of recovery or the performance of cache tier. But if there's no activity reported for a certain pool, we just reset the history of deltas of that pool. :Type: Integer :Default: ``10`` ``mon_osd_max_op_age`` :Description: Maximum op age before we get concerned (make it a power of 2). ``HEALTH_WARN`` will be raised if a request has been blocked longer than this limit. :Type: Float :Default: ``32.0`` ``osd_pg_bits`` :Description: Placement group bits per Ceph OSD Daemon. :Type: 32-bit Integer :Default: ``6`` ``osd_pgp_bits`` :Description: The number of bits per Ceph OSD Daemon for PGPs. :Type: 32-bit Integer :Default: ``6`` ``osd_crush_chooseleaf_type`` :Description: The bucket type to use for ``chooseleaf`` in a CRUSH rule. Uses ordinal rank rather than name. :Type: 32-bit Integer :Default: ``1``. Typically a host containing one or more Ceph OSD Daemons. ``osd_crush_initial_weight`` :Description: The initial CRUSH weight for newly added OSDs. :Type: Double :Default: ``the size of a newly added OSD in TB``. By default, the initial CRUSH weight for a newly added OSD is set to its device size in TB. See `Weighting Bucket Items`_ for details. ``osd_pool_default_crush_rule`` :Description: The default CRUSH rule to use when creating a replicated pool. :Type: 8-bit Integer :Default: ``-1``, which means "pick the rule with the lowest numerical ID and use that". This is to make pool creation work in the absence of rule 0. ``osd_pool_erasure_code_stripe_unit`` :Description: Sets the default size, in bytes, of a chunk of an object stripe for erasure coded pools. Every object of size S will be stored as N stripes, with each data chunk receiving ``stripe unit`` bytes. Each stripe of ``N * stripe unit`` bytes will be encoded/decoded individually. This option can is overridden by the ``stripe_unit`` setting in an erasure code profile. :Type: Unsigned 32-bit Integer :Default: ``4096`` ``osd_pool_default_size`` :Description: Sets the number of replicas for objects in the pool. The default value is the same as ``ceph osd pool set {pool-name} size {size}``. :Type: 32-bit Integer :Default: ``3`` ``osd_pool_default_min_size`` :Description: Sets the minimum number of written replicas for objects in the pool in order to acknowledge a write operation to the client. If minimum is not met, Ceph will not acknowledge the write to the client, **which may result in data loss**. This setting ensures a minimum number of replicas when operating in ``degraded`` mode. :Type: 32-bit Integer :Default: ``0``, which means no particular minimum. If ``0``, minimum is ``size - (size / 2)``. ``osd_pool_default_pg_num`` :Description: The default number of placement groups for a pool. The default value is the same as ``pg_num`` with ``mkpool``. :Type: 32-bit Integer :Default: ``32`` ``osd_pool_default_pgp_num`` :Description: The default number of placement groups for placement for a pool. The default value is the same as ``pgp_num`` with ``mkpool``. PG and PGP should be equal (for now). :Type: 32-bit Integer :Default: ``8`` ``osd_pool_default_flags`` :Description: The default flags for new pools. :Type: 32-bit Integer :Default: ``0`` ``osd_max_pgls`` :Description: The maximum number of placement groups to list. A client requesting a large number can tie up the Ceph OSD Daemon. :Type: Unsigned 64-bit Integer :Default: ``1024`` :Note: Default should be fine. ``osd_min_pg_log_entries`` :Description: The minimum number of placement group logs to maintain when trimming log files. :Type: 32-bit Int Unsigned :Default: ``250`` ``osd_max_pg_log_entries`` :Description: The maximum number of placement group logs to maintain when trimming log files. :Type: 32-bit Int Unsigned :Default: ``10000`` ``osd_default_data_pool_replay_window`` :Description: The time (in seconds) for an OSD to wait for a client to replay a request. :Type: 32-bit Integer :Default: ``45`` ``osd_max_pg_per_osd_hard_ratio`` :Description: The ratio of number of PGs per OSD allowed by the cluster before the OSD refuses to create new PGs. An OSD stops creating new PGs if the number of PGs it serves exceeds ``osd_max_pg_per_osd_hard_ratio`` \* ``mon_max_pg_per_osd``. :Type: Float :Default: ``2`` ``osd_recovery_priority`` :Description: Priority of recovery in the work queue. :Type: Integer :Default: ``5`` ``osd_recovery_op_priority`` :Description: Default priority used for recovery operations if pool doesn't override. :Type: Integer :Default: ``3`` .. _pool: ../../operations/pools .. _Monitoring OSDs and PGs: ../../operations/monitoring-osd-pg#peering .. _Weighting Bucket Items: ../../operations/crush-map#weightingbucketitems