Strengthened warning against multiple arbiters: (#999)

Author: mdb-ashley

source/core/replica-set-arbiter.txt

@@ -58,17 +58,18 @@ Replica Set Protocol Version and Arbiter
 
 .. _rollbacks-multi-arbiters:
 
-Concerns with Multiple Arbiters
--------------------------------
+Don't Deploy Multiple Arbiters
+------------------------------
 
 Use a single arbiter to avoid problems with data consistency. Multiple
-arbiters prevent the reliable use of the majority write concern.
+arbiters prevent the reliable use of the majority 
+:ref:`write concern <write-concern>`.
 
 To ensure that a write will persist after the failure of a primary node,
 the majority write concern requires a majority of nodes to acknowledge
 a write operation. Arbiters do not store any data, but they do
 contribute to the number of nodes in a replica set. When a replica set
-has multiple arbiters it is less likely that a majority of data bearing
+has multiple arbiters, it's less likely that a majority of data bearing
 nodes will be available after a node failure.
 
 .. warning::

source/includes/admonition-multiple-arbiters.rst

@@ -1,6 +1,6 @@
 .. warning:: 
 
-   Avoid deploying more than one arbiter per replica set.
+   Don't deploy more than one arbiter per replica set.
 
    See also: :ref:`rollbacks-multi-arbiters`
 

source/tutorial/add-replica-set-arbiter.txt

@@ -10,12 +10,12 @@ Add an Arbiter to Replica Set
    :depth: 1
    :class: singlecol
 
-In some circumstances (such as you have a primary and a secondary but
+In some circumstances (such as if you have a primary and a secondary but
 cost constraints prohibit adding another secondary), you may choose to
 add a :binary:`~bin.mongod` instance to a replica set as an
 :doc:`arbiter </core/replica-set-arbiter>` to vote in elections.
 
-Arbiters are :binary:`~bin.mongod` instances that are part of a
+Arbiters are ``mongod`` instances that are part of a
 :term:`replica set` but do not hold data (i.e. do not provide data
 redundancy). They can, however, participate in :ref:`elections
 <replica-set-elections>`.