Docsp 34246v7.0 -- cherry-picking from #29 (#32)

cherry-picking from #29 


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Author: jvincent-mongodb

source/core/requirements.txt

@@ -451,6 +451,13 @@ Intel/AMD (``x86_64``) Hardware Architectures
 
 .. _onprem-config-ulimits:
 
+Exec Options for ``/var`` Mount
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+|onprem| requires the default ``exec`` option defined in 
+``/etc/fstab`` on the underlying host machine in order to run the required 
+binaries stored in the volume backing the ``/var`` directory.
+
 Ulimits Requirements for |application|
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~