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| -rw-r--r-- | doc/rados/operations/crush-map.rst | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/doc/rados/operations/crush-map.rst b/doc/rados/operations/crush-map.rst index 96175665fe3..0d5ce22d390 100644 --- a/doc/rados/operations/crush-map.rst +++ b/doc/rados/operations/crush-map.rst @@ -482,18 +482,18 @@ A rule takes the following form:: :Example: ``step take data`` -``step choose [firstn|indep] {num} type {bucket-type}`` +``step choose [firstn|indep] [num] type {bucket-type}`` -:Description: Selects the number of buckets of the given type, which is usually the number of replicas in the pool. If ``{num} > 0 && < pool-num-replicas``, choose that many buckets; if ``{num} < 0``, it means ``pool-num-replicas - {num}``; and, if ``{num} == 0``, choose ``pool-num-replicas`` buckets (all available). +:Description: Selects the number of buckets of the given type, which is usually the number of replicas in the pool (i.e., pool size). If you choose ``indep``, do not specify ``[num]`` as it is not used. If you choose ``firstn``, you must specify a number for the ``[num]`` argument. If ``[num] > 0 && < pool-num-replicas``, choose that many buckets; if ``[num] < 0``, it means ``pool-num-replicas - [num]``; and, if ``[num] == 0``, choose ``pool-num-replicas`` buckets (all available). :Purpose: A component of the rule. :Prerequisite: Follows ``step take`` or ``step choose``. :Example: ``step choose firstn 1 type row`` :Note: The ``indep`` option isn't currently used, as Ceph doesn't support RAID at this time. -``step chooseleaf {num} type {bucket-type}`` +``step chooseleaf [firstn|indep] [num] type {bucket-type}`` -:Description: Selects the number of devices aggregated by a bucket of the given type. The number of devices is usually the number of replicas in the pool. If ``{num} > 0 && < pool-num-replicas``, choose that many buckets; if ``{num} < 0``, it means ``pool-num-replicas - {num}``; and, if ``{num} == 0``, choose ``pool-num-replicas`` buckets (all available). +:Description: Selects the number of devices aggregated by a bucket of the given type. If you choose ``indep``, do not specify ``[num]`` as it is not used. If you choose ``firstn``, you must specify a number for the ``[num]`` argument. The number of devices is usually the number of replicas in the pool (i.e., pool size). If ``[num] > 0 && < pool-num-replicas``, choose that many buckets; if ``[num] < 0``, it means ``pool-num-replicas - [num]``; and, if ``[num] == 0``, choose ``pool-num-replicas`` buckets (all available). :Purpose: A component of the rule. Usage removes the need to select a device using two steps. :Prerequisite: Follows ``step take`` or ``step choose``. :Example: ``step chooseleaf firstn 0 type row`` |