DOCS-557 add ref to cloneCollectionAsCapped in convertToCapped

source/reference/command/cloneCollectionAsCapped.txt

@@ -0,0 +1,38 @@
+=======================
+cloneCollectionAsCapped
+=======================
+
+.. default-domain:: mongodb
+
+.. dbcommand:: cloneCollectionAsCapped
+
+   The :dbcommand:`cloneCollectionAsCapped` command creates a new
+   :term:`capped collection` from an existing, non-capped collection
+   within the same database. The original non-capped collection
+   remains after the operation.
+
+   The command has the following syntax:
+
+   .. code-block:: javascript
+
+      { cloneCollectionAsCapped: <existing collection>, toCollection: <capped collection>, size: <capped size> }
+
+   The command copies an ``existing collection`` and creates a new
+   ``capped collection`` with a maximum size specified by the ``capped
+   size`` in bytes. The name of the new capped collection must be
+   distinct and cannot be the same as that of the original existing
+   collection. To replace the original non-capped collection with a
+   capped collection, use the :dbcommand:`convertToCapped` command.
+
+   During the cloning, the :dbcommand:`cloneCollectionAsCapped` command
+   exhibit the following behavior:
+
+   - The documents in the original collection will be traversed in
+     :term:`$natural order <natural order>` and loaded into a new
+     capped collection.
+
+   - If the ``capped size`` specified for the capped collection is
+     smaller than the size of the original uncapped collection, then
+     the documents will be aged out of the collection based on
+     insertion order(First In, First Out).
+

source/reference/command/convertToCapped.txt

@@ -7,7 +7,8 @@ convertToCapped
 .. dbcommand:: convertToCapped
 
    The :dbcommand:`convertToCapped` command converts an existing,
-   non-capped collection to a :term:`capped collection`.
+   non-capped collection to a :term:`capped collection` within the same
+   database.
 
    The command has the following syntax:
 
@@ -30,6 +31,14 @@ convertToCapped
      smaller than the size of the original uncapped collection, then
      the documents will be aged out of the collection based on
      insertion order(First In, First Out).
+
+   - The actual conversion process consists of the
+     :dbcommand:`cloneCollectionAsCapped` command followed by a
+     :dbcommand:`renameCollection` command. First, the
+     :dbcommand:`cloneCollectionAsCapped` command creates the capped
+     collection. Then, the original collection is dropped. Finally, the
+     :dbcommand:`renameCollection` command renames the new capped
+     collection to the name of the original collection.
 
    .. note::