Blob Store compress default to true

Changed default of compress setting from false to true for blob store
repositories. This aligns the code with documentation and also seems
like the better default.

Author: henningandersen

docs/reference/migration/migrate_8_0/snapshots.asciidoc

@@ -11,3 +11,14 @@ The `repositories.fs.compress` setting has been removed.
 
 Instead use the repository specific `compress` setting to enable compression. See <<modules-snapshots>> for information
 on the `compress` setting.
+
+[float]
+==== Compression of meta data files is now default on
+
+Previously, the default value for `compress` was `false`. The default has been changed to `true`. This aligns the
+default with documentation.
+
+This change will affect both newly created repositories and existing repositories where `compress=false` has not been
+explicitly specified.
+
+For more information on the compress option, see <<modules-snapshots>>

server/src/main/java/org/elasticsearch/repositories/blobstore/BlobStoreRepository.java

@@ -199,7 +199,7 @@ public abstract class BlobStoreRepository extends AbstractLifecycleComponent imp
      * files that are already compressed by default. Changing the setting does not invalidate existing files since reads
      * do not observe the setting, instead they examine the file to see if it is compressed or not.
      */
-    public static final Setting<Boolean> COMPRESS_SETTING = Setting.boolSetting("compress", false, Setting.Property.NodeScope);
+    public static final Setting<Boolean> COMPRESS_SETTING = Setting.boolSetting("compress", true, Setting.Property.NodeScope);
 
     private final Settings settings;