diff --git a/doc/mgr/index.rst b/doc/mgr/index.rst
index 0dad31e929f..0b03acfb938 100644
--- a/doc/mgr/index.rst
+++ b/doc/mgr/index.rst
@@ -45,3 +45,4 @@ sensible.
     Insights module <insights>
     Orchestrator module <orchestrator>
     Rook module <rook>
+    MDS Autoscaler module <mds_autoscaler>
diff --git a/doc/mgr/mds_autoscaler.rst b/doc/mgr/mds_autoscaler.rst
new file mode 100644
index 00000000000..39dadd88292
--- /dev/null
+++ b/doc/mgr/mds_autoscaler.rst
@@ -0,0 +1,31 @@
+MDS Autoscaler Module
+=====================
+
+The MDS Autoscaler Module monitors ``fsmap`` update notifications from the mgr
+daemon and takes action to spawn or kill MDS daemons for a file-system as per
+changes to the:
+
+- ``max_mds`` config value
+- ``standby_count_wanted`` config value
+- standby promotions to active MDS state in case of active MDS rank death
+
+Bumping up the ``max_mds`` config option value causes a standby mds to be promoted
+to hold an active rank. This leads to a drop in standby mds count. The MDS
+Autoscaler module detects this deficit and the orchestrator module is notified
+about the required MDS count. The orchestrator back-end then takes necessary
+measures to spawn standby MDSs.
+
+Dropping the ``max_mds`` config option causes the orchestrator back-end to kill
+standby mds to achieve the new reduced count. Preferably standby mds are chosen
+to be killed when the ``max_mds`` count is dropped.
+
+An increment and decrement of the ``standby_count_wanted`` config option value
+has a similar effect on the total MDS count. The orchestrator is notified about
+the change and necessary action to spawn or kill standby MDSs is taken.
+
+A death of an active MDS rank also causes promotion of a standby mds to occupy
+the required active rank. The MDS Autoscaler notices the change in the standby
+mds count and a message is passed to the orchestrator to maintain the necessary
+MDS count.
+
+NOTE: There is no CLI associated with the MDS Autoscaler Module.