Breaking up envvars and config settings into separate settings pages (#1028)

- Creates a slew of folders and pages nested under the mc-server page to store settings.
- Breaks up all of the environment variable options formerly in the mc-server page into these separate pages.
- Moves the config settings formerly in the mc admin config page to the appropriate new settings pages.
- Adds a MiniO Client settings page and document `mc-host-<alias>`

Closes #1017

source/reference/minio-server/settings/storage-class.rst

@@ -0,0 +1,91 @@
+.. _minio-server-envvar-storage-class:
+.. _minio-ec-storage-class:
+
+=====================
+Erasure Code Settings
+=====================
+
+.. default-domain:: minio
+
+.. contents:: Table of Contents
+   :local:
+   :depth: 2
+
+This page covers settings that configure the :ref:`Erasure Code <minio-erasure-coding>` :ref:`parity <minio-ec-parity>` to use for objects written to the MinIO cluster.
+This impacts how MinIO uses the space on the drive(s) and how MinIO can recover objects stored on lost drives or similar issues.
+
+.. note::
+
+   *MinIO Storage Classes* are distinct from *AWS Storage Classes*.
+
+   AWS Storage Classes refer to the specific storage tier on which to store a given object, such as ``hot`` or ``glacier`` storage.
+   MinIO Storage Classes affect the erasure code parity setting used and relate to :ref:`minio-availability-resiliency` of objects.
+
+   For tiering from one type of storage to another, such as for cost management purposes, see :ref:`minio-lifecycle-management-tiering`.
+
+Define any of these environment variables in the host system prior to starting or restarting the MinIO process.
+Refer to your operating system's documentation for how to define an environment variable.
+
+Environment Variables
+---------------------
+
+.. note::
+
+   These settings do not have configuration setting options for use with :mc:`mc admin config set`.
+
+.. envvar:: MINIO_STORAGE_CLASS_STANDARD
+
+   The :ref:`parity level <minio-ec-parity>` for the deployment.
+   MinIO shards objects written with the default ``STANDARD`` storage class using this parity value.
+
+   MinIO references the ``x-amz-storage-class`` header in request metadata for determining which storage class to assign an object. 
+   The specific syntax or method for setting headers depends on your preferred method for interfacing with the MinIO server.
+
+   Specify the value using ``EC:M`` notation, where ``M`` refers to the number of parity blocks to create for the object.
+
+   The following table lists the default values based on the :ref:`erasure set size <minio-ec-erasure-set>` of the initial server pool in the deployment:
+
+   .. list-table::
+      :header-rows: 1
+      :widths: 30 70
+      :width: 100%
+
+      * - Erasure Set Size
+        - Default Parity (EC:N)
+
+      * - 4-5
+        - EC:2
+
+      * - 6 - 7
+        - EC:3
+
+      * - 8 - 16
+        - EC:4
+
+   The minimum supported value is ``0``, which indicates no erasure coding protections.
+   These deployments rely entirely on the storage controller or resource for availability / resiliency. 
+   
+   The maximum value depends on the erasure set size of the initial server pool in the deployment, where the upper bound is  :math:`\frac{\text{ERASURE_SET_SIZE}}{\text{2}}`.
+   For example, a deployment with erasure set stripe size of 16 has a maximum standard parity of 8.
+
+   You can change this value after startup to any value between ``0`` and the upper bound for the erasure set size.
+   MinIO only applies the changed parity to newly written objects.
+   Existing objects retain the parity value in place at the time of their creation.
+
+.. envvar:: MINIO_STORAGE_CLASS_RRS
+
+   The :ref:`parity level <minio-ec-parity>` for objects written with the ``REDUCED`` storage class.
+
+   MinIO references the ``x-amz-storage-class`` header in request metadata for determining which storage class to assign an object. 
+   The specific syntax or method for setting headers depends on your preferred method for interfacing with the MinIO server.
+
+   Specify the value using ``EC:M`` notation, where ``M`` refers to the number of parity blocks to create for the object.
+
+   This value **must be** less than or equal to :envvar:`MINIO_STORAGE_CLASS_STANDARD`.
+
+   You cannot set this value for deployments with an erasure set size less than 5.
+   Defaults to ``EC:2``.
+
+.. envvar:: MINIO_STORAGE_CLASS_COMMENT
+
+   Adds a comment to the storage class settings.