Merge pull request #16650 from keszybz/two-doc-updates

Two doc updates

docs/DISCOVERABLE_PARTITIONS.md

@@ -9,21 +9,21 @@ _TL;DR: Let's automatically discover, mount and enable the root partition,
 `/home/`, `/srv/`, `/var/` and `/var/tmp/` and the swap partitions based on
 GUID Partition Tables (GPT)!_
 
-The GUID Partition Table (GPT) is mandatory on EFI systems. It allows
-identification of partition types with UUIDs. So far Linux has made little use
-of this, and mostly just defined one UUID for file system/data partitions and
-another one for swap partitions.  With this specification, we introduce
-additional partition types to enable automatic discovery of partitions and
-their intended mountpoint.  This has many benefits:
+This specification describes the use of GUID Partition Table (GPT) UUIDs to
+enable automatic discovery of partitions and their intended mountpoints.
+Traditionally Linux has made little use of partition types, mostly just
+defining one UUID for file system/data partitions and another one for swap
+partitions. With this specification, we introduce additional partition types
+for specific uses. This has many benefits:
 
 * OS installers can automatically discover and make sense of partitions of
   existing Linux installations.
-* The OS can discover and mount the necessary file systems with a non-existing
+* The OS can discover and mount the necessary file systems with a non-existent
   or incomplete `/etc/fstab` file and without the `root=` kernel command line
   option.
-* Container managers (such as nspawn and libvirt-lxc) can decode and set up
+* Container managers (such as nspawn and libvirt-lxc) can introspect and set up
   file systems contained in GPT disk images automatically and mount them to the
-  right places, thus allowing booting the same, identical images on bare-metal
+  right places, thus allowing booting the same, identical images on bare metal
   and in Linux containers. This enables true, natural portability of disk
   images between physical machines and Linux containers.
 * As a help to administrators and users partition manager tools can show more

man/journald.conf.xml

@@ -67,12 +67,18 @@
         <literal>persistent</literal>, data will be stored preferably on disk, i.e. below the
         <filename>/var/log/journal</filename> hierarchy (which is created if needed), with a fallback to
         <filename>/run/log/journal</filename> (which is created if needed), during early boot and if the disk
-        is not writable.  <literal>auto</literal> is similar to <literal>persistent</literal> but the
-        directory <filename>/var/log/journal</filename> is not created if needed, so that its existence
-        controls where log data goes.  <literal>none</literal> turns off all storage, all log data received
-        will be dropped. Forwarding to other targets, such as the console, the kernel log buffer, or a syslog
-        socket will still work however. Defaults to <literal>auto</literal> in the default journal namespace,
-        and <literal>persistent</literal> in all others.</para></listitem>
+        is not writable. <literal>auto</literal> behaves like <literal>persistent</literal> if the
+        <filename>/var/log/journal</filename> directory exists, and <literal>volatile</literal> otherwise
+        (the existence of the directory controls the storage mode). <literal>none</literal> turns off all
+        storage, all log data received will be dropped (but forwarding to other targets, such as the console,
+        the kernel log buffer, or a syslog socket will still work). Defaults to <literal>auto</literal> in
+        the default journal namespace, and <literal>persistent</literal> in all others.</para>
+
+        <para>Note that when this option is changed to <literal>volatile</literal>, existing persistent data
+        is not removed. In the other direction,
+        <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> with
+        the <option>--flush</option> option may be used to move volatile data to persistent storage.</para>
+        </listitem>
       </varlistentry>
 
       <varlistentry>