docs(admin): Move external storage encoding to main ext st. ch.

Move external storage specific file name encoding section out of the buried troubleshooting chapter and into the main external storage configuring chapter.

Also very light updates to formatting, grammar, and headings.

Very light misc clarification/clean-up.

Signed-off-by: Josh <[email protected]>

Author: joshtrichards

admin_manual/configuration_files/external_storage_configuration_gui.rst

@@ -1,43 +1,47 @@
-==================================
-Configuring External Storage (GUI)
-==================================
+================
+External Storage
+================
 
 The External Storage Support application enables you to mount external storage 
 services and devices as secondary Nextcloud storage devices. You may also allow 
 users to mount their own external storage services.
 
-For configuration of external storages via occ command, see :ref:`occ documentation <files_external_label>`.
+Enabling
+--------
 
-Enabling External Storage Support
----------------------------------
-
-The External storage support application is enabled on your Apps page.
+External Storage Support is provided by a bundled (automatically installed) app. It is 
+disabled by default, so to use this feature you simply need to enable it under
+**Apps**.
 
 .. figure:: external_storage/images/enable-app.png
    :alt: Enable external storage on your Apps page.
 
-Storage configuration
----------------------
+Configuring
+-----------
+
+To access the settings for configuring external storage mounts, click your Profile icon
+in the top right and select **Settings** from the dropdown. On the left side, under
+**Administration**, select **External Storage**.
 
-To access the settings for configuring external storage mounts, click on your Profile icon
-in the top right and select settings from the dropdown.  On the left side under Administration
-select External Storage.
+.. note::
+   External storage can also be configured via the occ command. See :ref:`occ 
+   documentation <files_external_label>`.
 
 To create a new external storage mount, select an available backend from the
-dropdown **Add storage**. Each backend has different required options, which 
+**Add storage** dropdown. Each backend has different required options, which 
 are configured in the configuration fields.
 
 .. figure:: external_storage/images/add_storage.png
 
 Each backend may also accept multiple authentication methods. These are selected 
 with the dropdown under **Authentication**. Different backends support different 
-authentication mechanisms; some specific to the backend, others are more 
+authentication mechanisms; some are specific to the backend, while others are more 
 generic. See :doc:`external_storage/auth_mechanisms` for more detailed 
 information.
 
 When you select an authentication mechanism, the configuration fields change as 
-appropriate for the mechanism. The SFTP backend, for one example, supports 
-**username and password**, **Log-in credentials, save in session**, and **RSA 
+appropriate for the chosen mechanism. For example, the SFTP backend supports 
+**Username and password**, **Log-in credentials, save in session**, and **RSA 
 public key**.
 
 .. figure:: external_storage/images/auth_mechanism.png
@@ -52,41 +56,40 @@ re-check your configuration and network availability.
 If there is an error on the storage, it will be marked as unavailable for ten 
 minutes. To re-check it, click the colored icon or reload your Admin page.
 
-Usage of variables for mount paths
+Usage of Variables for Mount Paths
 ----------------------------------
 
 The external storage mounting mechanism accepts variables in the mount path.
 
-Use ``$user`` for automatic substitution with the logged in user's username.
+Use ``$user`` for automatic substitution with the logged-in user's username.
 
 Use ``$home`` for automatic substitution with a configurable home directory variable
-(requires LDAP, see :ref:`LDAP_Special_Attributes` in the LDAP configuration documentation for details)
+(requires LDAP; see :ref:`LDAP_Special_Attributes` in the LDAP configuration documentation for details).
 
-In the following example, the mount point for a logged in user "alice" would substitute 
+In the following example, the mount point for a logged-in user "alice" would resolve 
 to ``/opt/userDirectories/alice/myPictures``.
 
 .. figure:: external_storage/images/externalStorages_variables.png
    :alt: External storage user variable substitution
 
-
-User and group permissions
+User and Group Permissions
 --------------------------
 
-A storage configured in a user's Personal settings is available only to the user 
-that created it. A storage configured in the Admin settings is available to 
-all users by default, and it can be restricted to specific users and groups in 
+A storage configured in a user's personal settings is available only to the user 
+who created it. A storage configured in the Admin settings is available to 
+all users by default, but it can be restricted to specific users and groups in 
 the **Available for** field.
 
 .. figure:: external_storage/images/applicable.png
    :alt: User and groups selector
 
 .. _external_storage_mount_options_label:
 
-Mount options
+Mount Options
 -------------
 
-The Overflow menu (three dots) exposes the settings and trashcan. Click the trashcan to delete the
-mountpoint. The settings button allows you to configure each storage mount
+The overflow menu (three dots) exposes the settings and trashcan icons. Click the trashcan to delete the
+mount point. The settings button allows you to configure each storage mount
 individually with the following options:
 
 * Encryption
@@ -99,23 +102,23 @@ individually with the following options:
 The **Encryption** checkbox is visible only when the Encryption app is enabled. Note that server-side
 encryption is not available for other Nextcloud servers used as external storage.
 
-**Enable Sharing** allows the Nextcloud admin to enable or disable sharing on individual mountpoints.
-When sharing is disabled the shares are retained internally, so that you can re-enable sharing
+**Enable Sharing** allows the Nextcloud admin to enable or disable sharing on individual mount points.
+When sharing is disabled, the shares are retained internally so that you can re-enable sharing
 and the previous shares become available again. Sharing is disabled by default.
 
 .. figure:: external_storage/images/mount_options.png
    :alt: Additional mount options exposed on mouseover.
 
-Using self-signed certificates
+Using Self-Signed Certificates
 ------------------------------
 
-When using self-signed certificates for external storage mounts the certificate
+When using self-signed certificates for external storage mounts, the certificate
 must be imported into the personal settings of the user. Please refer to 
 `Nextcloud HTTPS External Mount 
 <https://ownclouden.blogspot.de/2014/11/owncloud-https-external-mount.html>`_
 for more information.
 
-Available storage backends
+Available Storage Backends
 --------------------------
 
 The following backends are provided by the external storages app.
@@ -133,9 +136,9 @@ The following backends are provided by the external storages app.
     external_storage/webdav
 
 .. note:: A non-blocking or correctly configured SELinux setup is needed
-   for these backends to work. Please refer to the :ref:`selinux-config-label`.
+   for these backends to work. Please refer to :ref:`selinux-config-label`.
 
-Allow users to mount external Storage
+Allow Users to Mount External Storage
 -------------------------------------
 
 Check **Enable User External Storage** to allow your users to mount their own 
@@ -146,19 +149,48 @@ on your network!
 .. figure:: external_storage/images/user_mounts.png
    :alt: Checkboxes to allow users to mount external storage services.
 
-Adding files to external storages
----------------------------------
+Adding Files
+------------
 
 We recommend configuring the background job **Webcron** or
 **Cron** (see :doc:`../configuration_server/background_jobs_configuration`)
 to enable Nextcloud to automatically detect files added to your external
 storages.
 
-Nextcloud may not always be able to find out what has been
-changed remotely (files changed without going through Nextcloud), especially
-when it's very deep in the folder hierarchy of the external storage.
+Nextcloud may not always be able to detect changes made remotely (files changed without going through Nextcloud), especially
+when files are located deep in the folder hierarchy of the external storage.
 
-You might need to setup a cron job that runs ``sudo -E -u www-data php occ files:scan --all``
-(or replace ``--all`` with the user name, see also :doc:`../occ_command`)
-to trigger a rescan of the user's files periodically (for example every 15 minutes), which includes
+You might need to set up a cron job that runs ``sudo -E -u www-data php occ files:scan --all``
+(or replace ``--all`` with the username; see also :doc:`../occ_command`)
+to trigger a rescan of the user's files periodically (for example, every 15 minutes), which includes
 the mounted external storage.
+
+.. _trouble-file-encoding-ext-storages:
+
+Troubleshooting File Name Encoding
+----------------------------------
+
+.. TODO: This should be reviewed by a knowledgeable party at a future date to determine if any changes are relevant with the HFS+ to APFS migration in macOS.
+
+When using external storage, it can happen that some files with special characters will not
+appear in the file listing, or they will appear but not be accessible.
+
+When this happens, please run the :ref:`files scanner<occ_files_scan_label>`, for example::
+
+  sudo -E -u www-data php occ files:scan --all
+
+If the scanner reports an encoding issue on the affected file, please enable Mac encoding
+compatibility in the :ref:`mount options<external_storage_mount_options_label>`
+and then :ref:`rescan the external storage<occ_files_scan_label>`.
+
+.. note::
+   This mode comes with a performance impact because Nextcloud will always try both encodings when detecting files
+   on external storages.
+
+   Mac computers use the NFD Unicode normalization for file names, which is different from NFC, the one used
+   by other operating systems. Mac users might upload files directly to the external storage using NFD-normalized
+   file names. When uploading through Nextcloud, file names will always be normalized to the NFC standard for consistency.
+
+   It is recommended to let Nextcloud use external storages exclusively to avoid such issues.
+
+   See also the `technical explanation about NFC vs NFD normalizations <https://www.win.tue.nl/~aeb/linux/uc/nfc_vs_nfd.html>`_.