[couchdb-documentation] 15/18: add description of how quorum sizes are calculated

[wo...@apache.org]

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wohali pushed a commit to branch 2.2.0-release-notes
in repository https://gitbox.apache.org/repos/asf/couchdb-documentation.git

commit d005d14a0dde86119d15ebe15fa6dc0423cef5ed
Author: Diana Thayer <ga...@gmail.com>
AuthorDate: Fri Jul 20 08:38:20 2018 -0700

    add description of how quorum sizes are calculated
---
 src/cluster/sharding.rst | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/cluster/sharding.rst b/src/cluster/sharding.rst
index 51b1630..5aa81c5 100644
--- a/src/cluster/sharding.rst
+++ b/src/cluster/sharding.rst
@@ -87,7 +87,11 @@ the other nodes that have the relevant data, which may or may not
 include itself. The coordinating node sends a response to the client
 once a `quorum
 <https://en.wikipedia.org/wiki/Quorum_(distributed_computing)>`__ of
-database nodes have responded; 2, by default.
+database nodes have responded; 2, by default. The default required size
+of a quorum is equal to ``r=w=((n+1)/2)`` where ``r`` refers to the size
+of a read quorum, ``w`` refers to the size of a write quorum, and ``n`` refers to
+the number of replicas of each shard. In a default cluster where ``n``
+is 3, ``((n+1)/2)`` would be 2.
 
 .. note::
     Each node in a cluster can be a coordinating node for any one