DOCS-471: ulimit page: edits

Author: Bob Grabar

draft/administration/ulimit.txt

@@ -3,7 +3,7 @@ Linux ``ulimit`` Settings
 =========================
 
 The Linux kernel provides a system to limit and control the number of
-threads, connections, open files, on a per-process and per-user
+threads, connections, and open files on a per-process and per-user
 basis. These limits prevent renegade processes from using too many
 system resources. Sometimes, these limits, as configured by the
 distribution developers, are too low for MongoDB and can cause a
@@ -13,35 +13,37 @@ Resource Utilization
 --------------------
 
 :program:`mongod` and :program:`mongos` each use threads and file
-descriptors to track connections, and manage internal operations. This
-section outlines the general resource utilization patterns for
-MongoDB. Use these figures in combination with the actual
+descriptors to track connections and manage internal operations. This
+section outlines the general resource utilization patterns for MongoDB.
+Use these figures in combination with the actual information about your
+deployment and its use to determine ideal ``ulimit`` settings.
 
 ``mongod``
 ~~~~~~~~~~
 
-- 1 thread for each incoming connection from clients and, for
-  :term:`replica sets <replica set>`, other :program:`mongod` instances.
+- 1 thread for each incoming connection from a client and for
+  each incoming connection from a :program:`mongod` instance in a
+  :term:`replica set <replica set>`.
 
-- 1 thread for each outgoing connection to another :program:`mongod`
-  when running in a replica set.
+- 1 thread for each outgoing connection to a :program:`mongod`
+  in a replica set.
 
 - 1 file descriptor for each incoming connection.
 
 - 1 file descriptor for each data file in used by the
   :program:`mongod` instance.
 
 - 1 file descriptor for each journal file used by the
-  :program:`mongod` instance (when :setting:`journal` is ``true``.)
+  :program:`mongod` instance when :setting:`journal` is ``true``.
 
-:program:`mongod` uses threads for a number of internal processes
-including :ref:`TTL collections <ttl-collections>` and replication
+:program:`mongod` uses threads for a number of internal processes,
+including :ref:`TTL collections <ttl-collections>` and replication,
 which may require a small number of additional resources.
 
 ``mongos``
 ~~~~~~~~~~
 
-- 1 thread for each incoming connection from clients.
+- 1 thread for each incoming connection from a client.
 
 - 1 file descriptor for each incoming connection.
 
@@ -55,18 +57,20 @@ For :program:`mongos`, consider the following behaviors:
   fulfill requests without needing to create new connections.
 
 - The size of the connection pool is configurable with the
-  :setting:`maxConns` runtime options (i.e. :option:`--maxConns
-  <mongos --maxConns>`.)
+  :setting:`maxConns` runtime options:
+
+  ..code-block:: javascript
+
+    :option:`--maxConns <mongos --maxConns>`
 
 Review and Set Resource Limits
 ------------------------------
 
-
 ``ulimit``
 ~~~~~~~~~~
 
 You can use the ``ulimit`` command at the system prompt to check
-system limits, as in the following example
+system limits, as in the following example:
 
 .. code-block:: sh
 
@@ -90,13 +94,13 @@ system limits, as in the following example
 
 ``ulimit`` refers to the per-*user* limitations for various
 resources. Therefore, if your :program:`mongod` instance executes as a
-user that is also running other processes, you can see some contention
+user that is also running other processes, you might see some contention
 for these resources. Also, be aware that the ``processes`` value
 (i.e. ``-u``) refers to the combined number of distinct processes and
 sub-process threads.
 
 You can change ``ulimit`` settings by issuing a command in the
-following form: ::
+following form:
 
 .. code-block:: sh
 
@@ -115,6 +119,10 @@ Substitute the ``-n`` option for any possible value in the output of
 ``/proc`` File System
 ~~~~~~~~~~~~~~~~~~~~~
 
+.. note:: 
+
+   This section applies only to Linux operating systems.
+
 The ``/proc`` file-system stores the per-process limits in the
 file system object located at ``/proc/<pid>/limits``, where ``<pid>``
 is the processes :term:`PID` or process identifier. You can use the
@@ -141,7 +149,7 @@ object for a process or processes with a given name:
 
    }
 
-You can copy and paste this function into a current shell session, or
+You can copy and paste this function into a current shell session or
 load it as part of a script. Call the function with one the following
 invocations: