fixup! docs on storage and consistency

docs/best_practice/multi_node_setup.txt

@@ -134,19 +134,26 @@ where ``N`` is the maximum number of nodes in the cluster.
   start to elect a master on their own. This can cause data loss and
   inconsistencies.
 
-  Also, if the planned number of nodes changes in a cluster, the quorum
-  needs to be updated too, since it should never get below the half of
-  the available nodes, but also should allow for operation without
-  having all nodes online, so it should not be too high to.
+  Also, if the planned number of nodes changes in a cluster, the
+  quorum needs to be updated too. This is not only because the quorum
+  should never get below the half of the available nodes, but also
+  should allow for operation without having all nodes online, so it
+  should not be too high to.
+
 
 For example, in a 3-node cluster it would mean that at least 2 nodes
 need to see each other before they are allowed to elect a master. So
-the following line needs to be added to the configuration file.
-
-::
+the following line needs to be added to the configuration file::
 
   discovery.zen.minimum_master_nodes: 2
 
+or on an already running cluster it is also possible to set it using
+the following statement:
+
+.. code-block:: psql
+
+  SET GLOBAL PERSISTENT discovery.zen.minimum_master_nodes = 2;
+
 .. note::
 
   Given the formula above it means that in a cluster with a maximum of

docs/best_practice/multi_zone_setup.txt

@@ -1,3 +1,5 @@
+.. _multi_zone_setup:
+
 ================
 Multi Zone Setup
 ================

docs/storage_consistency.txt

@@ -29,22 +29,36 @@ fetching data from a specific marker.
 
 An arbitrary number of replica shards can be configured per
 table. Every operational replica holds a full synchronized copy of the
-primary shard. Writes are synchronous over all active replicas with
-the following flow:
+primary shard.
 
-1. The operation is routed to the according primary shard for
+In terms of read operations, there is no difference between executing
+the operation on the primary shard or on any of the replicas. Crate
+randomly assigns a shard when routing an operation. However it is
+possible to configure this behaviour if required - for example in a
+:ref:`multi_zone_setup`.
+
+Write operations are handled differently than reads. Such operations
+are synchronous over all active replicas with the following flow:
+
+1. The primary shard and the active replicas are looked up in the
+   cluster state for the given operation. The primary shard and a
+   quorum of the configured replicas need to be available for this
+   step to succeed.
+
+2. The operation is routed to the according primary shard for
    execution.
 
-2. The operation gets executed on the primary shard
+3. The operation gets executed on the primary shard
 
-3. If the operation succeeds on the primary, the operation gets
+4. If the operation succeeds on the primary, the operation gets
    executed on all replicas in parallel.
 
-4. After all replica operations are finished the operation result gets
+5. After all replica operations are finished the operation result gets
    returned to the caller.
 
 Should any replica shard fail to write the data or times out in step
-4, it is immediatly considered as unavailable.
+5, it is immediatly considered as unavailable.
+
 
 Atomic on Document Level
 ========================
@@ -77,7 +91,7 @@ operations are permanent.
 
 The translog is also directly transfered when a newly allocated
 replica initialises itself from the primary shard. So there is no need
-to flush segements to disc just for replica-recovery purposes.
+to flush segments to disc just for replica-recovery purposes.
 
 Adressing of Documents
 ======================
@@ -113,7 +127,7 @@ Consistency
 Crate is eventual consistent for search operations. Search operations
 are performed on shared ``IndexReaders`` which besides other
 functionalities, provide caching and reverse lookup capabilities for
-shards. An ``IndexReader`` is always bound to the Lucene_ segement it
+shards. An ``IndexReader`` is always bound to the Lucene_ segment it
 was started from, which means it has to be refreshed in order to see
 new changes, this is done on a time based mannner, but can also be
 done manually (see :ref:`refresh_data`). Therefore a search only sees