pools for storing data. A pool provides you with:
- **Resilience**: You can set how many OSD are allowed to fail without losing data.
- For replicated pools, it is the desired number of copies/replicas of an object.
+ For replicated pools, it is the desired number of copies/replicas of an object.
A typical configuration stores an object and one additional copy
(i.e., ``size = 2``), but you can determine the number of copies/replicas.
For `erasure coded pools <../erasure-code>`_, it is the number of coding chunks
(i.e. ``m=2`` in the **erasure code profile**)
-
+
- **Placement Groups**: You can set the number of placement groups for the pool.
- A typical configuration uses approximately 100 placement groups per OSD to
- provide optimal balancing without using up too many computing resources. When
+ A typical configuration uses approximately 100 placement groups per OSD to
+ provide optimal balancing without using up too many computing resources. When
setting up multiple pools, be careful to ensure you set a reasonable number of
- placement groups for both the pool and the cluster as a whole.
+ placement groups for both the pool and the cluster as a whole.
-- **CRUSH Rules**: When you store data in a pool, a CRUSH ruleset mapped to the
- pool enables CRUSH to identify a rule for the placement of the object
- and its replicas (or chunks for erasure coded pools) in your cluster.
+- **CRUSH Rules**: When you store data in a pool, a CRUSH ruleset mapped to the
+ pool enables CRUSH to identify a rule for the placement of the object
+ and its replicas (or chunks for erasure coded pools) in your cluster.
You can create a custom CRUSH rule for your pool.
-
-- **Snapshots**: When you create snapshots with ``ceph osd pool mksnap``,
+
+- **Snapshots**: When you create snapshots with ``ceph osd pool mksnap``,
you effectively take a snapshot of a particular pool.
-
-To organize data into pools, you can list, create, and remove pools.
+
+To organize data into pools, you can list, create, and remove pools.
You can also view the utilization statistics for each pool.
List Pools
==========
-To list your cluster's pools, execute::
+To list your cluster's pools, execute::
ceph osd lspools
application using the pool. See `Associate Pool to Application`_ below for
more information.
-For example::
+For example::
osd pool default pg num = 100
osd pool default pgp num = 100
-To create a pool, execute::
+To create a pool, execute::
ceph osd pool create {pool-name} {pg-num} [{pgp-num}] [replicated] \
[crush-rule-name] [expected-num-objects]
ceph osd pool create {pool-name} {pg-num} {pgp-num} erasure \
[erasure-code-profile] [crush-rule-name] [expected_num_objects]
-Where:
+Where:
``{pool-name}``
``{pg-num}``
:Description: The total number of placement groups for the pool. See `Placement
- Groups`_ for details on calculating a suitable number. The
+ Groups`_ for details on calculating a suitable number. The
default value ``8`` is NOT suitable for most systems.
:Type: Integer
``{pgp-num}``
:Description: The total number of placement groups for placement purposes. This
- **should be equal to the total number of placement groups**, except
+ **should be equal to the total number of placement groups**, except
for placement group splitting scenarios.
:Type: Integer
implement a subset of the available operations.
:Type: String
-:Required: No.
+:Required: No.
:Default: replicated
``[crush-rule-name]``
rule must exist.
:Type: String
-:Required: No.
+:Required: No.
:Default: For **replicated** pools it is the ruleset specified by the ``osd
pool default crush replicated ruleset`` config variable. This
ruleset must exist.
.. _erasure code profile: ../erasure-code-profile
:Description: For **erasure** pools only. Use the `erasure code profile`_. It
- must be an existing profile as defined by
+ must be an existing profile as defined by
**osd erasure-code-profile set**.
:Type: String
-:Required: No.
+:Required: No.
When you create a pool, set the number of placement groups to a reasonable value
(e.g., ``100``). Consider the total number of placement groups per OSD too.
:Type: Integer
:Required: No.
-:Default: 0, no splitting at the pool creation time.
+:Default: 0, no splitting at the pool creation time.
Associate Pool to Application
=============================
Set Pool Quotas
===============
-You can set pool quotas for the maximum number of bytes and/or the maximum
+You can set pool quotas for the maximum number of bytes and/or the maximum
number of objects per pool. ::
- ceph osd pool set-quota {pool-name} [max_objects {obj-count}] [max_bytes {bytes}]
+ ceph osd pool set-quota {pool-name} [max_objects {obj-count}] [max_bytes {bytes}]
-For example::
+For example::
ceph osd pool set-quota data max_objects 10000
See `Monitor Configuration`_ for more information.
.. _Monitor Configuration: ../../configuration/mon-config-ref
-
+
If you created your own rulesets and rules for a pool you created, you should
consider removing them when you no longer need your pool::
Rename a Pool
=============
-To rename a pool, execute::
+To rename a pool, execute::
ceph osd pool rename {current-pool-name} {new-pool-name}
-If you rename a pool and you have per-pool capabilities for an authenticated
+If you rename a pool and you have per-pool capabilities for an authenticated
user, you must update the user's capabilities (i.e., caps) with the new pool
-name.
+name.
.. note:: Version ``0.48`` Argonaut and above.
Show Pool Statistics
====================
-To show a pool's utilization statistics, execute::
+To show a pool's utilization statistics, execute::
rados df
-
+
Make a Snapshot of a Pool
=========================
-To make a snapshot of a pool, execute::
+To make a snapshot of a pool, execute::
+
+ ceph osd pool mksnap {pool-name} {snap-name}
- ceph osd pool mksnap {pool-name} {snap-name}
-
.. note:: Version ``0.48`` Argonaut and above.
Remove a Snapshot of a Pool
===========================
-To remove a snapshot of a pool, execute::
+To remove a snapshot of a pool, execute::
ceph osd pool rmsnap {pool-name} {snap-name}
-.. note:: Version ``0.48`` Argonaut and above.
+.. note:: Version ``0.48`` Argonaut and above.
.. _setpoolvalues:
Set Pool Values
===============
-To set a value to a pool, execute the following::
+To set a value to a pool, execute the following::
ceph osd pool set {pool-name} {key} {value}
-
-You may set values for the following keys:
+
+You may set values for the following keys:
.. _compression_algorithm:
``compression_algorithm``
+
:Description: Sets inline compression algorithm to use for underlying BlueStore.
This setting overrides the `global setting <rados/configuration/bluestore-config-ref/#inline-compression>`_ of ``bluestore compression algorithm``.
``size``
-:Description: Sets the number of replicas for objects in the pool.
- See `Set the Number of Object Replicas`_ for further details.
+:Description: Sets the number of replicas for objects in the pool.
+ See `Set the Number of Object Replicas`_ for further details.
Replicated pools only.
:Type: Integer
``min_size``
-:Description: Sets the minimum number of replicas required for I/O.
- See `Set the Number of Object Replicas`_ for further details.
+:Description: Sets the minimum number of replicas required for I/O.
+ See `Set the Number of Object Replicas`_ for further details.
Replicated pools only.
:Type: Integer
``pg_num``
-:Description: The effective number of placement groups to use when calculating
+:Description: The effective number of placement groups to use when calculating
data placement.
:Type: Integer
:Valid Range: Superior to ``pg_num`` current value.
``pgp_num``
-:Description: The effective number of placement groups for placement to use
+:Description: The effective number of placement groups for placement to use
when calculating data placement.
:Type: Integer
:Description: Set/Unset HASHPSPOOL flag on a given pool.
:Type: Integer
:Valid Range: 1 sets flag, 0 unsets flag
-:Version: Version ``0.48`` Argonaut and above.
+:Version: Version ``0.48`` Argonaut and above.
.. _nodelete:
``hit_set_count``
-:Description: The number of hit sets to store for cache pools. The higher
+:Description: The number of hit sets to store for cache pools. The higher
the number, the more RAM consumed by the ``ceph-osd`` daemon.
:Type: Integer
``hit_set_period``
-:Description: The duration of a hit set period in seconds for cache pools.
- The higher the number, the more RAM consumed by the
+:Description: The duration of a hit set period in seconds for cache pools.
+ The higher the number, the more RAM consumed by the
``ceph-osd`` daemon.
:Type: Integer
``cache_target_dirty_ratio``
-:Description: The percentage of the cache pool containing modified (dirty)
+:Description: The percentage of the cache pool containing modified (dirty)
objects before the cache tiering agent will flush them to the
backing storage pool.
-
+
:Type: Double
:Default: ``.4``
:Description: The percentage of the cache pool containing unmodified (clean)
objects before the cache tiering agent will evict them from the
cache pool.
-
+
:Type: Double
:Default: ``.8``
``target_max_bytes``
-:Description: Ceph will begin flushing or evicting objects when the
+:Description: Ceph will begin flushing or evicting objects when the
``max_bytes`` threshold is triggered.
-
+
:Type: Integer
:Example: ``1000000000000`` #1-TB
.. _target_max_objects:
-``target_max_objects``
+``target_max_objects``
-:Description: Ceph will begin flushing or evicting objects when the
+:Description: Ceph will begin flushing or evicting objects when the
``max_objects`` threshold is triggered.
:Type: Integer
``cache_min_flush_age``
-:Description: The time (in seconds) before the cache tiering agent will flush
+:Description: The time (in seconds) before the cache tiering agent will flush
an object from the cache pool to the storage pool.
-
+
:Type: Integer
-:Example: ``600`` 10min
+:Example: ``600`` 10min
.. _cache_min_evict_age:
:Description: The time (in seconds) before the cache tiering agent will evict
an object from the cache pool.
-
+
:Type: Integer
:Example: ``1800`` 30min
Get Pool Values
===============
-To get a value from a pool, execute the following::
+To get a value from a pool, execute the following::
ceph osd pool get {pool-name} {key}
-
-You may get values for the following keys:
+
+You may get values for the following keys:
``size``
``cache_target_full_ratio``
:Description: see cache_target_full_ratio_
-
+
:Type: Double
``target_max_bytes``
:Description: see target_max_bytes_
-
+
:Type: Integer
-``target_max_objects``
+``target_max_objects``
:Description: see target_max_objects_
``cache_min_flush_age``
:Description: see cache_min_flush_age_
-
+
:Type: Integer
``cache_min_evict_age``
:Description: see cache_min_evict_age_
-
+
:Type: Integer
Set the Number of Object Replicas
=================================
-To set the number of object replicas on a replicated pool, execute the following::
+To set the number of object replicas on a replicated pool, execute the following::
ceph osd pool set {poolname} size {num-replicas}
.. important:: The ``{num-replicas}`` includes the object itself.
- If you want the object and two copies of the object for a total of
+ If you want the object and two copies of the object for a total of
three instances of the object, specify ``3``.
-
-For example::
+
+For example::
ceph osd pool set data size 3
-You may execute this command for each pool. **Note:** An object might accept
+You may execute this command for each pool. **Note:** An object might accept
I/Os in degraded mode with fewer than ``pool size`` replicas. To set a minimum
number of required replicas for I/O, you should use the ``min_size`` setting.
For example::
Get the Number of Object Replicas
=================================
-To get the number of object replicas, execute the following::
+To get the number of object replicas, execute the following::
ceph osd dump | grep 'replicated size'
-
+
Ceph will list the pools, with the ``replicated size`` attribute highlighted.
-By default, ceph creates two replicas of an object (a total of three copies, or
+By default, ceph creates two replicas of an object (a total of three copies, or
a size of 3).
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