diff --git a/core/src/main/scala/org/apache/spark/storage/BlockManagerMasterEndpoint.scala b/core/src/main/scala/org/apache/spark/storage/BlockManagerMasterEndpoint.scala
index 8e8f7d197c9e..f984cf76e346 100644
--- a/core/src/main/scala/org/apache/spark/storage/BlockManagerMasterEndpoint.scala
+++ b/core/src/main/scala/org/apache/spark/storage/BlockManagerMasterEndpoint.scala
@@ -54,7 +54,8 @@ class BlockManagerMasterEndpoint(
   // Mapping from block id to the set of block managers that have the block.
   private val blockLocations = new JHashMap[BlockId, mutable.HashSet[BlockManagerId]]
 
-  private val askThreadPool = ThreadUtils.newDaemonCachedThreadPool("block-manager-ask-thread-pool")
+  private val askThreadPool =
+    ThreadUtils.newDaemonCachedThreadPool("block-manager-ask-thread-pool", 100)
   private implicit val askExecutionContext = ExecutionContext.fromExecutorService(askThreadPool)
 
   private val topologyMapper = {
diff --git a/core/src/main/scala/org/apache/spark/storage/BlockManagerSlaveEndpoint.scala b/core/src/main/scala/org/apache/spark/storage/BlockManagerSlaveEndpoint.scala
index 742cf4fe393f..67544b20408a 100644
--- a/core/src/main/scala/org/apache/spark/storage/BlockManagerSlaveEndpoint.scala
+++ b/core/src/main/scala/org/apache/spark/storage/BlockManagerSlaveEndpoint.scala
@@ -37,7 +37,7 @@ class BlockManagerSlaveEndpoint(
   extends ThreadSafeRpcEndpoint with Logging {
 
   private val asyncThreadPool =
-    ThreadUtils.newDaemonCachedThreadPool("block-manager-slave-async-thread-pool")
+    ThreadUtils.newDaemonCachedThreadPool("block-manager-slave-async-thread-pool", 100)
   private implicit val asyncExecutionContext = ExecutionContext.fromExecutorService(asyncThreadPool)
 
   // Operations that involve removing blocks may be slow and should be done asynchronously