(DOCSP-28903): Clarify default oplog size bounds (#7374) (#7400)

* (DOCSP-28903): Clarify default oplog size bounds

* edit

* Update source/core/replica-set-oplog.txt



* WIP

* review feedback

* simplify

* reformatting

* reformatting

* remove page from other pr

* standardize formatting

* standardize order

---------

Co-authored-by: jocelyn-mendez1 <[email protected]>

Author: jeff-allen-mongo

source/core/replica-set-oplog.txt

@@ -47,36 +47,39 @@ Oplog Size
 ----------
 
 When you start a replica set member for the first time, MongoDB creates
-an oplog of a default size if you do not specify the oplog size. 
+an oplog of a default size if you do not specify the oplog size.
 
 For Unix and Windows systems
    The default oplog size depends on the storage engine:
 
    .. list-table::
-      :widths: 30 30 20 20
+      :widths: 50 50
       :header-rows: 1
 
       * - Storage Engine
         - Default Oplog Size
-        - Lower Bound
-        - Upper Bound
 
-      * - :doc:`/core/inmemory`
+      * - :ref:`storage-wiredtiger`
 
-        -  5% of physical memory
+        - 5% of free disk space
 
-        - 50 MB
+      * - :ref:`storage-inmemory`
 
-        - 50 GB
+        - 5% of physical memory
 
-      * - :doc:`/core/wiredtiger`
-        - 5% of free disk space
-        - 990 MB 
-        - 50 GB
+   The default oplog size has the following constraints:
+
+   - The minimum oplog size is 990 MB. If 5% of free disk space or
+     physical memory (whichever is applicable based on your storage
+     engine) is less than 990 MB, the default oplog size is 990 MB.
+
+   - The maximum default oplog size is 50 GB. If 5% of free disk space or
+     physical memory (whichever is applicable based on your storage
+     engine) is greater than 50 GB, the default oplog size is 50 GB.
 
 For 64-bit macOS systems
-   The default oplog size is 192 MB of either physical memory or free
-   disk space depending on the storage engine:
+   The default oplog size is 192 MB of either free disk space or
+   physical memory depending on the storage engine:
 
    .. list-table::
       :widths: 50 50
@@ -85,13 +88,13 @@ For 64-bit macOS systems
       * - Storage Engine
         - Default Oplog Size
 
-      * - :doc:`/core/inmemory`
+      * - :ref:`storage-wiredtiger`
 
-        - 192 MB of physical memory
-
-      * - :doc:`/core/wiredtiger`
         - 192 MB of free disk space
 
+      * - :ref:`storage-inmemory`
+
+        - 192 MB of physical memory
 
 In most cases, the default oplog size is sufficient. For example, if an
 oplog is 5% of free disk space and fills up in 24 hours of operations,