1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
|
=======
Pools
=======
When you first deploy a cluster without creating a pool, Ceph uses the default
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.
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
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.
- **CRUSH Rules**: When you store data in a pool, placement of the object
and its replicas (or chunks for erasure coded pools) in your cluster is governed
by CRUSH rules. You can create a custom CRUSH rule for your pool if the default
rule is not appropriate for your use case.
- **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.
You can also view the utilization statistics for each pool.
List Pools
==========
To list your cluster's pools, execute::
ceph osd lspools
.. _createpool:
Create a Pool
=============
Before creating pools, refer to the `Pool, PG and CRUSH Config Reference`_.
Ideally, you should override the default value for the number of placement
groups in your Ceph configuration file, as the default is NOT ideal.
For details on placement group numbers refer to `setting the number of placement groups`_
.. note:: Starting with Luminous, all pools need to be associated to the
application using the pool. See `Associate Pool to Application`_ below for
more information.
For example::
osd pool default pg num = 100
osd pool default pgp num = 100
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:
``{pool-name}``
:Description: The name of the pool. It must be unique.
:Type: String
:Required: Yes.
``{pg-num}``
:Description: The total number of placement groups for the pool. See `Placement
Groups`_ for details on calculating a suitable number. The
default value ``8`` is NOT suitable for most systems.
:Type: Integer
:Required: Yes.
:Default: 8
``{pgp-num}``
:Description: The total number of placement groups for placement purposes. This
**should be equal to the total number of placement groups**, except
for placement group splitting scenarios.
:Type: Integer
:Required: Yes. Picks up default or Ceph configuration value if not specified.
:Default: 8
``{replicated|erasure}``
:Description: The pool type which may either be **replicated** to
recover from lost OSDs by keeping multiple copies of the
objects or **erasure** to get a kind of
`generalized RAID5 <../erasure-code>`_ capability.
The **replicated** pools require more
raw storage but implement all Ceph operations. The
**erasure** pools require less raw storage but only
implement a subset of the available operations.
:Type: String
:Required: No.
:Default: replicated
``[crush-rule-name]``
:Description: The name of a CRUSH rule to use for this pool. The specified
rule must exist.
:Type: String
:Required: No.
:Default: For **replicated** pools it is the rule specified by the ``osd
pool default crush rule`` config variable. This rule must exist.
For **erasure** pools it is ``erasure-code`` if the ``default``
`erasure code profile`_ is used or ``{pool-name}`` otherwise. This
rule will be created implicitly if it doesn't exist already.
``[erasure-code-profile=profile]``
.. _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
**osd erasure-code-profile set**.
:Type: String
: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.
Placement groups are computationally expensive, so performance will degrade when
you have many pools with many placement groups (e.g., 50 pools with 100
placement groups each). The point of diminishing returns depends upon the power
of the OSD host.
See `Placement Groups`_ for details on calculating an appropriate number of
placement groups for your pool.
.. _Placement Groups: ../placement-groups
``[expected-num-objects]``
:Description: The expected number of objects for this pool. By setting this value (
together with a negative **filestore merge threshold**), the PG folder
splitting would happen at the pool creation time, to avoid the latency
impact to do a runtime folder splitting.
:Type: Integer
:Required: No.
:Default: 0, no splitting at the pool creation time.
.. _associate-pool-to-application:
Associate Pool to Application
=============================
Pools need to be associated with an application before use. Pools that will be
used with CephFS or pools that are automatically created by RGW are
automatically associated. Pools that are intended for use with RBD should be
initialized using the ``rbd`` tool (see `Block Device Commands`_ for more
information).
For other cases, you can manually associate a free-form application name to
a pool.::
ceph osd pool application enable {pool-name} {application-name}
.. note:: CephFS uses the application name ``cephfs``, RBD uses the
application name ``rbd``, and RGW uses the application name ``rgw``.
Set Pool Quotas
===============
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}]
For example::
ceph osd pool set-quota data max_objects 10000
To remove a quota, set its value to ``0``.
Delete a Pool
=============
To delete a pool, execute::
ceph osd pool delete {pool-name} [{pool-name} --yes-i-really-really-mean-it]
To remove a pool the mon_allow_pool_delete flag must be set to true in the Monitor's
configuration. Otherwise they will refuse to remove a pool.
See `Monitor Configuration`_ for more information.
.. _Monitor Configuration: ../../configuration/mon-config-ref
If you created your own rules for a pool you created, you should consider
removing them when you no longer need your pool::
ceph osd pool get {pool-name} crush_rule
If the rule was "123", for example, you can check the other pools like so::
ceph osd dump | grep "^pool" | grep "crush_rule 123"
If no other pools use that custom rule, then it's safe to delete that
rule from the cluster.
If you created users with permissions strictly for a pool that no longer
exists, you should consider deleting those users too::
ceph auth ls | grep -C 5 {pool-name}
ceph auth del {user}
Rename a Pool
=============
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
user, you must update the user's capabilities (i.e., caps) with the new pool
name.
Show Pool Statistics
====================
To show a pool's utilization statistics, execute::
rados df
Additionally, to obtain I/O information for a specific pool or all, execute::
ceph osd pool stats [{pool-name}]
Make a Snapshot of a Pool
=========================
To make a snapshot of a pool, execute::
ceph osd pool mksnap {pool-name} {snap-name}
Remove a Snapshot of a Pool
===========================
To remove a snapshot of a pool, execute::
ceph osd pool rmsnap {pool-name} {snap-name}
.. _setpoolvalues:
Set Pool Values
===============
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:
.. _compression_algorithm:
``compression_algorithm``
:Description: Sets inline compression algorithm to use for underlying BlueStore. This setting overrides the `global setting <http://docs.ceph.com/docs/master/rados/configuration/bluestore-config-ref/#inline-compression>`_ of ``bluestore compression algorithm``.
:Type: String
:Valid Settings: ``lz4``, ``snappy``, ``zlib``, ``zstd``
``compression_mode``
:Description: Sets the policy for the inline compression algorithm for underlying BlueStore. This setting overrides the `global setting <http://docs.ceph.com/docs/master/rados/configuration/bluestore-config-ref/#inline-compression>`_ of ``bluestore compression mode``.
:Type: String
:Valid Settings: ``none``, ``passive``, ``aggressive``, ``force``
``compression_min_blob_size``
:Description: Chunks smaller than this are never compressed. This setting overrides the `global setting <http://docs.ceph.com/docs/master/rados/configuration/bluestore-config-ref/#inline-compression>`_ of ``bluestore compression min blob *``.
:Type: Unsigned Integer
``compression_max_blob_size``
:Description: Chunks larger than this are broken into smaller blobs sizing
``compression_max_blob_size`` before being compressed.
:Type: Unsigned Integer
.. _size:
``size``
: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:
``min_size``
: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
:Version: ``0.54`` and above
.. _pg_num:
``pg_num``
: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:
``pgp_num``
:Description: The effective number of placement groups for placement to use
when calculating data placement.
:Type: Integer
:Valid Range: Equal to or less than ``pg_num``.
.. _crush_rule:
``crush_rule``
:Description: The rule to use for mapping object placement in the cluster.
:Type: String
.. _allow_ec_overwrites:
``allow_ec_overwrites``
:Description: Whether writes to an erasure coded pool can update part
of an object, so cephfs and rbd can use it. See
`Erasure Coding with Overwrites`_ for more details.
:Type: Boolean
:Version: ``12.2.0`` and above
.. _hashpspool:
``hashpspool``
:Description: Set/Unset HASHPSPOOL flag on a given pool.
:Type: Integer
:Valid Range: 1 sets flag, 0 unsets flag
.. _nodelete:
``nodelete``
:Description: Set/Unset NODELETE flag on a given pool.
:Type: Integer
:Valid Range: 1 sets flag, 0 unsets flag
:Version: Version ``FIXME``
.. _nopgchange:
``nopgchange``
:Description: Set/Unset NOPGCHANGE flag on a given pool.
:Type: Integer
:Valid Range: 1 sets flag, 0 unsets flag
:Version: Version ``FIXME``
.. _nosizechange:
``nosizechange``
:Description: Set/Unset NOSIZECHANGE flag on a given pool.
:Type: Integer
:Valid Range: 1 sets flag, 0 unsets flag
:Version: Version ``FIXME``
.. _write_fadvise_dontneed:
``write_fadvise_dontneed``
:Description: Set/Unset WRITE_FADVISE_DONTNEED flag on a given pool.
:Type: Integer
:Valid Range: 1 sets flag, 0 unsets flag
.. _noscrub:
``noscrub``
:Description: Set/Unset NOSCRUB flag on a given pool.
:Type: Integer
:Valid Range: 1 sets flag, 0 unsets flag
.. _nodeep-scrub:
``nodeep-scrub``
:Description: Set/Unset NODEEP_SCRUB flag on a given pool.
:Type: Integer
:Valid Range: 1 sets flag, 0 unsets flag
.. _hit_set_type:
``hit_set_type``
:Description: Enables hit set tracking for cache pools.
See `Bloom Filter`_ for additional information.
:Type: String
:Valid Settings: ``bloom``, ``explicit_hash``, ``explicit_object``
:Default: ``bloom``. Other values are for testing.
.. _hit_set_count:
``hit_set_count``
: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
:Valid Range: ``1``. Agent doesn't handle > 1 yet.
.. _hit_set_period:
``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
``ceph-osd`` daemon.
:Type: Integer
:Example: ``3600`` 1hr
.. _hit_set_fpp:
``hit_set_fpp``
:Description: The false positive probability for the ``bloom`` hit set type.
See `Bloom Filter`_ for additional information.
:Type: Double
:Valid Range: 0.0 - 1.0
:Default: ``0.05``
.. _cache_target_dirty_ratio:
``cache_target_dirty_ratio``
: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``
.. _cache_target_dirty_high_ratio:
``cache_target_dirty_high_ratio``
:Description: The percentage of the cache pool containing modified (dirty)
objects before the cache tiering agent will flush them to the
backing storage pool with a higher speed.
:Type: Double
:Default: ``.6``
.. _cache_target_full_ratio:
``cache_target_full_ratio``
: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:
``target_max_bytes``
: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``
:Description: Ceph will begin flushing or evicting objects when the
``max_objects`` threshold is triggered.
:Type: Integer
:Example: ``1000000`` #1M objects
``hit_set_grade_decay_rate``
:Description: Temperature decay rate between two successive hit_sets
:Type: Integer
:Valid Range: 0 - 100
:Default: ``20``
``hit_set_search_last_n``
:Description: Count at most N appearance in hit_sets for temperature calculation
:Type: Integer
:Valid Range: 0 - hit_set_count
:Default: ``1``
.. _cache_min_flush_age:
``cache_min_flush_age``
: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
.. _cache_min_evict_age:
``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
.. _fast_read:
``fast_read``
:Description: On Erasure Coding pool, if this flag is turned on, the read request
would issue sub reads to all shards, and waits until it receives enough
shards to decode to serve the client. In the case of jerasure and isa
erasure plugins, once the first K replies return, client's request is
served immediately using the data decoded from these replies. This
helps to tradeoff some resources for better performance. Currently this
flag is only supported for Erasure Coding pool.
:Type: Boolean
:Defaults: ``0``
.. _scrub_min_interval:
``scrub_min_interval``
:Description: The minimum interval in seconds for pool scrubbing when
load is low. If it is 0, the value osd_scrub_min_interval
from config is used.
:Type: Double
:Default: ``0``
.. _scrub_max_interval:
``scrub_max_interval``
:Description: The maximum interval in seconds for pool scrubbing
irrespective of cluster load. If it is 0, the value
osd_scrub_max_interval from config is used.
:Type: Double
:Default: ``0``
.. _deep_scrub_interval:
``deep_scrub_interval``
:Description: The interval in seconds for pool “deep” scrubbing. If it
is 0, the value osd_deep_scrub_interval from config is used.
:Type: Double
:Default: ``0``
.. _recovery_priority:
``recovery_priority``
:Description: When a value is set it will increase or decrease the computed
reservation priority. This value must be in the range -10 to
10. Use a negative priority for less important pools so they
have lower priority than any new pools.
:Type: Integer
:Default: ``0``
.. _recovery_op_priority:
``recovery_op_priority``
:Description: Specify the recovery operation priority for this pool instead of ``osd_recovery_op_priority``.
:Type: Integer
:Default: ``0``
Get Pool Values
===============
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:
``size``
:Description: see size_
:Type: Integer
``min_size``
:Description: see min_size_
:Type: Integer
:Version: ``0.54`` and above
``pg_num``
:Description: see pg_num_
:Type: Integer
``pgp_num``
:Description: see pgp_num_
:Type: Integer
:Valid Range: Equal to or less than ``pg_num``.
``crush_rule``
:Description: see crush_rule_
``hit_set_type``
:Description: see hit_set_type_
:Type: String
:Valid Settings: ``bloom``, ``explicit_hash``, ``explicit_object``
``hit_set_count``
:Description: see hit_set_count_
:Type: Integer
``hit_set_period``
:Description: see hit_set_period_
:Type: Integer
``hit_set_fpp``
:Description: see hit_set_fpp_
:Type: Double
``cache_target_dirty_ratio``
:Description: see cache_target_dirty_ratio_
:Type: Double
``cache_target_dirty_high_ratio``
:Description: see cache_target_dirty_high_ratio_
:Type: Double
``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``
:Description: see target_max_objects_
:Type: Integer
``cache_min_flush_age``
:Description: see cache_min_flush_age_
:Type: Integer
``cache_min_evict_age``
:Description: see cache_min_evict_age_
:Type: Integer
``fast_read``
:Description: see fast_read_
:Type: Boolean
``scrub_min_interval``
:Description: see scrub_min_interval_
:Type: Double
``scrub_max_interval``
:Description: see scrub_max_interval_
:Type: Double
``deep_scrub_interval``
:Description: see deep_scrub_interval_
:Type: Double
``allow_ec_overwrites``
:Description: see allow_ec_overwrites_
:Type: Boolean
``recovery_priority``
:Description: see recovery_priority_
:Type: Integer
``recovery_op_priority``
:Description: see recovery_op_priority_
:Type: Integer
Set the Number of Object Replicas
=================================
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
three instances of the object, specify ``3``.
For example::
ceph osd pool set data size 3
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::
ceph osd pool set data min_size 2
This ensures that no object in the data pool will receive I/O with fewer than
``min_size`` replicas.
Get the Number of Object Replicas
=================================
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
a size of 3).
.. _Pool, PG and CRUSH Config Reference: ../../configuration/pool-pg-config-ref
.. _Bloom Filter: https://en.wikipedia.org/wiki/Bloom_filter
.. _setting the number of placement groups: ../placement-groups#set-the-number-of-placement-groups
.. _Erasure Coding with Overwrites: ../erasure-code#erasure-coding-with-overwrites
.. _Block Device Commands: ../../../rbd/rados-rbd-cmds/#create-a-block-device-pool
|