minor: correcting faulty titles

Author: Sam Kleinman

source/administration/backups.txt

@@ -568,8 +568,8 @@ perform restorations.
 
 .. _sharded-cluster-backups:
 
-Back Up Sharded Clusters
-~~~~~~~~~~~~~~~~~~~~~~~~
+Backup Sharded Clusters
+~~~~~~~~~~~~~~~~~~~~~~~
 
 Sharding complicates backup operations, because it is impossible to
 create a backup of a single moment in time from a distributed cluster
@@ -579,8 +579,8 @@ Depending on the size of your data, you can back up the cluster as a
 whole or back up each :program:`mongod` instance. The following
 section describes both procedures.
 
-Back Up the Cluster as a Whole Using ``mongodump``
-``````````````````````````````````````````````````
+Backup the Cluster as a Whole Using ``mongodump``
+`````````````````````````````````````````````````
 
 If your :term:`sharded cluster` comprises a small collection of data,
 you can connect to a :program:`mongos` and issue the
@@ -607,7 +607,7 @@ is true:
    :program:`mongodump` when dumping from a :program:`mongos`. This option is only
    available when running directly against a :term:`replica set` member.
 
-Back Up from All Database Instances
+Backup from All Database Instances
 ```````````````````````````````````
 
 If your :term:`sharded cluster` is to large for the :program:`mongodump`
@@ -637,9 +637,9 @@ This procedure describes both approaches:
       could have duplicate data or miss some data, as :term:`chunks
       <chunk>` migrate while recording backups.
 
-#. Lock one member of each replica set in shard so that your backups reflect your
-   entire database system at a single point in time. Lock all shards
-   in as short of an interval as possible.
+#. Lock one member of each replica set in each shard so that your backups reflect your
+   entire database system at a single point in time. Lock these
+   :program:`mongod` instances in as short of an interval as possible.
 
    To lock or freeze a sharded cluster, you must: