DOCS-8106: Tag Aware High Availibility Writes

source/images/metadata.yaml

@@ -1001,6 +1001,17 @@ output:
 ---
 name: sharding-tiered-slas-tags
 alt: "Diagram of sharded cluster architecture for tiered SLA"
+output:
+  - type: print
+    tag: 'print'
+    dpi: 300
+    width: 900
+  - type: web
+    dpi: 72
+    width: 700
+---
+name: sharded-cluster-high-availability-architecture
+alt: "Diagram of sharded cluster architecture for high availability"
 output:
   - type: print
     tag: 'print'

source/includes/steps-sharding-high-availability.yaml

@@ -0,0 +1,88 @@
+stepnum: 1
+title: Tag each shard.
+level: 4
+ref: sharding-high-availability-tag-shards
+action:
+  - pre: |
+      Tag each shard in the ``alfa`` data center with the ``alfa`` tag.
+    language: javascript
+    code: |
+      sh.addShardTag("shard0000", "alfa")
+  - pre: |
+      Tag each shard in the ``bravo`` data center with the ``bravo`` tag.
+    language: javascript
+    code: |
+      sh.addShardTag("shard0001", "bravo")
+post: |
+  You can review the tags assigned to any given shard by running 
+  :method:`sh.status()`. 
+---
+stepnum: 2
+title: Define ranges for each tag.
+level: 4
+ref: sharding-high-availability-tag-ranges
+action:
+  - pre: |
+      Define the range for the ``alfa`` database and associate it to the ``alfa`` 
+      tag using the :method:`sh.addTagRange()` method. This method requires:
+
+      * The full namespace of the target collection.
+
+      * The inclusive lower bound of the range.
+
+      * The exclusive upper bound of the range.
+
+      * The name of the tag.
+
+    language: javascript
+    code: |
+      sh.addTagRange( 
+        "<database>.<collection>",
+        { "datacenter" : "alfa", "userid" : MinKey },
+        { "datacenter" : "alfa", "userid" : MaxKey }, 
+        "alfa"
+      )
+  - pre: |
+      Define the range for the ``bravo`` database and associate it to the 
+      ``bravo`` tag using the :method:`sh.addTagRange()` method. This method 
+      requires:
+
+      * The full namespace of the target collection.
+
+      * The inclusive lower bound of the range.
+
+      * The exclusive upper bound of the range.
+
+      * The name of the tag.
+
+    language: javascript
+    code: |
+      sh.addTagRange( 
+        "<database>.<collection>",
+        { "datacenter" : "bravo", "userid" : MinKey },
+        { "datacenter" : "bravo", "userid" : MaxKey }, 
+        "bravo"
+      )
+post: |
+  The :bsontype:`MinKey` and :bsontype:`MaxKey` values are reserved special
+  values for comparisons. :bsontype:`MinKey` always compares as less than
+  every other possible value, while :bsontype:`MaxKey` always compares as
+  greater than every other possible value. The configured ranges capture every
+  user for each ``datacenter``.
+---
+stepnum: 3
+title: Review the changes.
+level: 4
+ref: sharding-high-availability-review
+pre: |
+  The next time the :ref:`balancer <sharding-balancing>` runs, it 
+  :ref:`splits <sharding-chunk-split>` and
+  :ref:`migrates <sharding-chunk-migration>` chunks across the 
+  shards respecting the tag ranges and tags. 
+
+  Once balancing finishes, the shards tagged as ``alfa`` should only
+  contain documents with ``datacenter : alfa``, while shards tagged as 
+  ``bravo`` should only contain documents with ``datacenter : bravo``.
+
+  You can review the chunk distribution by running :method:`sh.status()`.
+...

source/includes/toc-sharding-tag-aware.yaml

@@ -13,4 +13,8 @@ description: |
 file: /tutorial/sharding-segmenting-shards
 description: |
   Segmenting Shards based on Application or Customer using Tag Aware Sharding
+---
+file: /tutorial/sharding-high-availability-writes
+description: |
+  Tutorial on facilitating high availability writes using Tag Aware Sharding
 ...

source/reference/read-preference.txt

@@ -1,3 +1,5 @@
+.. _read-preference:
+
 =========================
 Read Preference Reference
 =========================