Change default recovery throttling to 50MB / sec

The current setting of 20MB/sec seems to be too conservative given
the capabilities of modern hardware / network throughput.
A 50MB default should provide better out of the box performance.

docs/reference/modules/indices.asciidoc

@@ -72,5 +72,5 @@ The following settings can be set to control the store throttling:
     could be `merge` (default), `not` or `all`. See <<index-modules-store>>.
 
 `indices.store.throttle.max_bytes_per_sec`::
-    defaults to `20mb`.
+    defaults to `50mb`.
 

src/main/java/org/elasticsearch/indices/recovery/RecoverySettings.java

@@ -81,7 +81,7 @@ public class RecoverySettings extends AbstractComponent {
         this.concurrentSmallFileStreams = componentSettings.getAsInt("concurrent_small_file_streams", settings.getAsInt("index.shard.recovery.concurrent_small_file_streams", 2));
         this.concurrentSmallFileStreamPool = EsExecutors.newScaling(0, concurrentSmallFileStreams, 60, TimeUnit.SECONDS, EsExecutors.daemonThreadFactory(settings, "[small_file_recovery_stream]"));
 
-        this.maxBytesPerSec = componentSettings.getAsBytesSize("max_bytes_per_sec", componentSettings.getAsBytesSize("max_size_per_sec", new ByteSizeValue(20, ByteSizeUnit.MB)));
+        this.maxBytesPerSec = componentSettings.getAsBytesSize("max_bytes_per_sec", componentSettings.getAsBytesSize("max_size_per_sec", new ByteSizeValue(50, ByteSizeUnit.MB)));
         if (maxBytesPerSec.bytes() <= 0) {
             rateLimiter = null;
         } else {

src/test/java/org/elasticsearch/test/ImmutableTestCluster.java

@@ -44,6 +44,7 @@ import org.elasticsearch.index.merge.scheduler.SerialMergeSchedulerProvider;
 import org.elasticsearch.index.translog.TranslogService;
 import org.elasticsearch.indices.IndexMissingException;
 import org.elasticsearch.indices.IndexTemplateMissingException;
+import org.elasticsearch.indices.recovery.RecoverySettings;
 import org.elasticsearch.indices.store.IndicesStore;
 import org.elasticsearch.repositories.RepositoryMissingException;
 import org.elasticsearch.search.SearchService;
@@ -284,6 +285,14 @@ public abstract class ImmutableTestCluster implements Iterable<Client> {
             builder.put(IndicesStore.INDICES_STORE_THROTTLE_TYPE, RandomPicks.randomFrom(random, StoreRateLimiting.Type.values()));
         }
 
+        if (random.nextBoolean()) {
+            if (random.nextInt(10) == 0) { // do something crazy slow here
+                builder.put(RecoverySettings.INDICES_RECOVERY_MAX_BYTES_PER_SEC, new ByteSizeValue(RandomInts.randomIntBetween(random, 1, 10), ByteSizeUnit.MB));
+            } else {
+                builder.put(RecoverySettings.INDICES_RECOVERY_MAX_BYTES_PER_SEC, new ByteSizeValue(RandomInts.randomIntBetween(random, 10, 200), ByteSizeUnit.MB));
+            }
+        }
+
         return builder;
     }