diff --git a/core/src/main/scala/org/apache/spark/internal/config/package.scala b/core/src/main/scala/org/apache/spark/internal/config/package.scala
index 05b2624b4037..2dcd3af7a52d 100644
--- a/core/src/main/scala/org/apache/spark/internal/config/package.scala
+++ b/core/src/main/scala/org/apache/spark/internal/config/package.scala
@@ -165,7 +165,7 @@ package object config {
     ConfigBuilder("spark.eventLog.compress")
       .version("1.0.0")
       .booleanConf
-      .createWithDefault(false)
+      .createWithDefault(true)
 
   private[spark] val EVENT_LOG_BLOCK_UPDATES =
     ConfigBuilder("spark.eventLog.logBlockUpdates.enabled")
diff --git a/docs/configuration.md b/docs/configuration.md
index 8fda9317bc77..e9ed2a8aa37d 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -1311,7 +1311,7 @@ Apart from these, the following properties are also available, and may be useful
 </tr>
 <tr>
   <td><code>spark.eventLog.compress</code></td>
-  <td>false</td>
+  <td>true</td>
   <td>
     Whether to compress logged events, if <code>spark.eventLog.enabled</code> is true.
   </td>
diff --git a/docs/core-migration-guide.md b/docs/core-migration-guide.md
index 3f97a484e1a6..765c3494f669 100644
--- a/docs/core-migration-guide.md
+++ b/docs/core-migration-guide.md
@@ -22,6 +22,10 @@ license: |
 * Table of contents
 {:toc}
 
+## Upgrading from Core 3.4 to 4.0
+
+- Since Spark 4.0, Spark will compress event logs. To restore the behavior before Spark 4.0, you can set `spark.eventLog.compress` to `false`.
+
 ## Upgrading from Core 3.3 to 3.4
 
 - Since Spark 3.4, Spark driver will own `PersistentVolumnClaim`s and try to reuse if they are not assigned to live executors. To restore the behavior before Spark 3.4, you can set `spark.kubernetes.driver.ownPersistentVolumeClaim` to `false` and `spark.kubernetes.driver.reusePersistentVolumeClaim` to `false`.