====================================== Pool, PG and CRUSH Config Reference ====================================== .. index:: pools; configuration When you create pools and set the number of placement groups for the pool, Ceph uses default values when you don't specifically override the defaults. **We recommend** overridding 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`` ``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 into crushmap. :Type: Double :Default: ``the size of newly added osd in TB``. By default, the initial crush weight for the newly added osd is set to its volume size in TB. See `Weighting Bucket Items`_ for details. ``osd pool default crush replicated ruleset`` :Description: The default CRUSH ruleset to use when creating a replicated pool. :Type: 8-bit Integer :Default: ``CEPH_DEFAULT_CRUSH_REPLICATED_RULESET``, which means "pick a ruleset with the lowest numerical ID and use that". This is to make pool creation work in the absence of ruleset 0. ``osd pool erasure code stripe width`` :Description: Sets the desired size, in bytes, of an object stripe on every erasure coded pools. Every object if size S will be stored as N stripes and each stripe will be encoded/decoded individually. :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. 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: ``8`` ``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: ``1000`` ``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`` .. _pool: ../../operations/pools .. _Monitoring OSDs and PGs: ../../operations/monitoring-osd-pg#peering .. _Weighting Bucket Items: ../../operations/crush-map#weightingbucketitems