ARTEMIS-2246 clarify docs for defaults; change max-disk-usage default

artemis-core-client/src/main/java/org/apache/activemq/artemis/api/config/ActiveMQDefaultConfiguration.java

@@ -467,7 +467,7 @@ public static String getDefaultHapolicyBackupStrategy() {
 
    public static final long DEFAULT_GLOBAL_MAX_SIZE = Runtime.getRuntime().maxMemory() / 2;
 
-   public static final int DEFAULT_MAX_DISK_USAGE = 100;
+   public static final int DEFAULT_MAX_DISK_USAGE = 90;
 
    public static final int DEFAULT_DISK_SCAN = 5000;
 

artemis-server/src/main/resources/schema/artemis-configuration.xsd

@@ -752,7 +752,7 @@
          <xsd:element name="max-disk-usage" type="xsd:int" default="90" maxOccurs="1" minOccurs="0">
             <xsd:annotation>
                <xsd:documentation>
-                  Max percentage of disk usage before the system blocks or fail clients.
+                  Max percentage of disk usage before the system blocks or fails clients.
                </xsd:documentation>
             </xsd:annotation>
          </xsd:element>

docs/user-manual/en/configuration-index.md

@@ -79,6 +79,16 @@ This is to help you customize artemis on embedded systems.
 This describes the root of the XML configuration. You will see here also multiple sub-types listed.
 For example on the main config you will have bridges and at the [list of bridge](#bridge-type) type we will describe the properties for that configuration.
 
+> **Warning**
+>
+> The default values listed below are the values which will be used if
+> the configuration parameter is **not set** either programmatically or
+> via `broker.xml`. Some of these values are set in the `broker.xml`
+> which is available out-of-the-box. Any values set in the
+> out-of-the-box configuration will override the default values listed
+> here. Please consult your specific configuration to know which values
+> will actually be used when the broker is running.
+
 Name | Description | Default
 ---|---|---
 [acceptors](configuring-transports.md#acceptors) | a list of remoting acceptors | n/a
@@ -135,7 +145,7 @@ log-delegate-factory-class-name | **deprecated** the name of the factory class t
 [management-notification-address](management.md#configuring-the-management-notification-address) | the name of the address that consumers bind to receive management notifications. | `activemq.notifications`
 [mask-password](masking-passwords.md) | This option controls whether passwords in server configuration need be masked. If set to "true" the passwords are masked. | `false`
 [max-saved-replicated-journals-size](ha.md#data-replication) | This specifies how many times a replicated backup server can restart after moving its files on start. Once there are this number of backup journal files the server will stop permanently after if fails back. -1 Means no Limit; 0 don't keep a copy at all. | 2
-[max-disk-usage](paging.md#max-disk-usage) | The max percentage of data we should use from disks. The System will block while the disk is full. Disable by setting -1. | 100
+[max-disk-usage](paging.md#max-disk-usage) | The max percentage of data we should use from disks. The broker will block while the disk is full. Disable by setting -1. | 90
 [memory-measure-interval](perf-tuning.md) | frequency to sample JVM memory in ms (or -1 to disable memory sampling). | -1
 [memory-warning-threshold](perf-tuning.md)| Percentage of available memory which will trigger a warning log. | 25
 [message-counter-enabled](management.md#message-counters) | true means that message counters are enabled. | `false`