DOCS-5665, DOCS-5782, DOCS-6898, DOCS-7445: platform-specific considerations

source/administration/production-notes.txt

@@ -492,20 +492,23 @@ When running MongoDB in production on Linux, you should use Linux
 kernel version 2.6.36 or later, with either the XFS or EXT4 filesystem.
 If possible, use XFS as it generally performs better with MongoDB.
 
-With the WiredTiger storage engine in particular, use of XFS is
-**strongly recommended** to avoid performance issues that have been
-observed when using EXT4 with WiredTiger.
+With the :ref:`WiredTiger storage engine <storage-wiredtiger>`, use of
+XFS is **strongly recommended** to avoid performance issues that may
+occur when using EXT4 with WiredTiger.
 
-- If you use the XFS file system, use at least version
+With the :ref:`MMAPv1 storage engine <storage-mmapv1>`, MongoDB
+preallocates its database files before using them and often creates
+large files. As such, you should use the XFS or EXT4 file systems. If
+possible, use XFS as it generally performs better with MongoDB.
+
+- In general, if you use the XFS file system, use at least version
   ``2.6.25`` of the Linux Kernel.
 
   .. Required for fallocate()
 
 - If you use the EXT4 file system, use at least version
   ``2.6.28`` of the Linux Kernel.
 
-  .. Initial stable release
-
 - On Red Hat Enterprise Linux and CentOS, use at least version
   ``2.6.18-194`` of the Linux kernel.
 
@@ -522,31 +525,43 @@ observed when using EXT4 with WiredTiger.
 Recommended Configuration
 `````````````````````````
 
-For the WiredTiger and MMAPv1 storage engines,
+For **all** MongoDB deployments:
+
+- Use the Network Time Protocol (NTP) to synchronize time among
+  your hosts. This is especially important in sharded clusters.
+
+For the **WiredTiger and MMAPv1** storage engines,
 consider the following recommendations:
 
 - Turn off ``atime`` for the storage volume containing the :term:`database
   files <dbpath>`.
 
 - Set the file descriptor limit, ``-n``, and the user process limit
   (ulimit), ``-u``, above 20,000, according to the suggestions in the
-  :doc:`ulimit </reference/ulimit>` document. A low ulimit will affect
+  :doc:`ulimit </reference/ulimit>` reference. A low ulimit will affect
   MongoDB when under heavy use and can produce errors and lead to
   failed connections to MongoDB processes and loss of service.
 
-- Disable Transparent Huge Pages, as MongoDB performs better with
+- Disable Transparent Huge Pages. MongoDB performs better with
   normal (4096 bytes) virtual memory pages. See :doc:`Transparent Huge
   Pages Settings </tutorial/transparent-huge-pages>`.
 
 - Disable NUMA in your BIOS. If that is not possible, see
   :ref:`MongoDB on NUMA Hardware <production-numa>`.
 
-- Configure SELinux on Red Hat. For more information, see
+- Problems have been reported when using MongoDB with SELinux enabled.
+  To avoid issues, disable SELinux when possible. 
+
+  If you are using SELinux on Red Hat, you must configure SELinux
+  to be able to run MongoDB. See: 
   :ref:`Configure SELinux for MongoDB <install-rhel-configure-selinux>`
   and :ref:`Configure SELinux for MongoDB Enterprise
-  <install-enterprise-rhel-configure-selinux>`.
+  <install-enterprise-rhel-configure-selinux>` for the required
+  configuration.
+
+  .. include:: /includes/fact-selinux-server-side-js.rst
 
-For the MMAPv1 storage engine:
+For the **MMAPv1** storage engine:
 
 .. _readahead:
 
@@ -559,11 +574,6 @@ For the MMAPv1 storage engine:
   <device>`` to change the readahead settings. Refer to your specific
   operating system manual for more information.
 
-For **all** MongoDB deployments:
-
-- Use the Network Time Protocol (NTP) to synchronize time among
-  your hosts. This is especially important in sharded clusters.
-
 MongoDB and TLS/SSL Libraries
 `````````````````````````````
 
@@ -680,11 +690,18 @@ instances directly from |MMS|. See :mms-docs:`Configure AWS Integration
 Azure
 `````
 
-For all MongoDB deployments using Azure, you **must** mount the volume
+Use `Premium Storage 
+<https://azure.microsoft.com/en-us/documentation/articles/storage-premium-storage/>`_. 
+Microsoft Azure offers two general types of storage:
+Standard storage, and Premium storage. MongoDB on Azure has better
+performance when using Premium storage than it does with Standard
+storage.
+
+For all :ref:`MMAPv1 <storage-mmapv1>` MongoDB deployments using Azure,
+you **must** mount the volume
 that hosts the :program:`mongod` instance's :setting:`~storage.dbPath`
 with the *Host Cache Preference* ``READ/WRITE``.
-
-This applies to all Azure deployments, using any guest operating
+This applies to all Azure deployments running MMAPv1, using any guest operating
 system.
 
 If your volumes have inappropriate cache settings, MongoDB may

source/core/server-side-javascript.txt

@@ -36,6 +36,8 @@ run on the server. For more information, see
 You can also disable server-side execution of JavaScript. For details,
 see :ref:`disable-server-side-js`.
 
+.. include:: /includes/fact-selinux-server-side-js.rst
+
 .. _running-js-scripts-in-mongo-on-mongod-host:
 
 Running ``.js`` files via a ``mongo`` shell Instance on the Server

source/includes/fact-selinux-redhat-options.rst

@@ -1,46 +1,42 @@
 .. important::
 
-   You must configure SELinux to allow MongoDB to start on Red Hat
-   Linux-based systems (Red Hat Enterprise Linux or CentOS Linux).
+   If you are using SELinux, you must configure SELinux to allow
+   MongoDB to start on Red Hat Linux-based systems (Red Hat Enterprise
+   Linux or CentOS Linux).
 
 To configure SELinux, administrators have three options:
 
-.. note::
+- If SELinux is in ``enforcing`` mode,
+  enable access to the relevant ports that the MongoDB deployment will use
+  (e.g. ``27017``). See :doc:`/reference/default-mongodb-port` for
+  more information on MongoDB's default ports. For default settings,
+  this can be accomplished by running
+
+  .. code-block:: sh
 
-   All three options require ``root`` privileges. The first two options
-   each requires a system reboot and may have larger implications for
-   your deployment.
+     semanage port -a -t mongod_port_t -p tcp 27017
 
-- Disable SELinux entirely by changing the ``SELINUX`` setting to
+- Disable SELinux by setting the ``SELINUX`` setting to
   ``disabled`` in ``/etc/selinux/config``.
 
   .. code-block:: sh
 
      SELINUX=disabled
+
+  You must reboot the system for the changes to take effect.
 
 - Set SELinux to ``permissive`` mode in ``/etc/selinux/config`` by
-  changing the ``SELINUX`` setting to ``permissive`` .
+  setting the ``SELINUX`` setting to ``permissive``.
 
   .. code-block:: sh
 
      SELINUX=permissive
 
-  .. note::
-
-     You can use ``setenforce`` to change to permissive mode; this
-     method does not require a reboot but is **not** persistent.
-
-- Enable access to the relevant ports (e.g. 27017) for SELinux if in
-  ``enforcing`` mode. See :doc:`/reference/default-mongodb-port` for
-  more information on MongoDB's default ports. For default settings,
-  this can be accomplished by running
-
-  .. code-block:: sh
-
-     semanage port -a -t mongod_port_t -p tcp 27017
+  You must reboot the system for the changes to take effect.
 
-  .. include:: /includes/warning-selinux-rhel7.rst
+  You can instead use ``setenforce`` to change to ``permissive`` mode.
+  ``setenforce`` does not require a reboot but is **not** persistent.
 
-You may alternatively choose not to install the SELinux packages when you are
+Alternatively, you can choose not to install the SELinux packages when you are
 installing your Linux operating system, or choose to remove the relevant
 packages. This option is the most invasive and is not recommended.

source/includes/fact-selinux-server-side-js.rst

@@ -0,0 +1,6 @@
+.. note::
+
+   If you are using SELinux, any MongoDB operation that requires
+   :doc:`server-side JavaScript </core/server-side-javascript>` will
+   result in segfault errors. :ref:`disable-server-side-js` describes
+   how to disable execution of server-side JavaScript.