diff --git a/block-storage/src/main/java/org/lucares/pdb/map/PersistentMap.java b/block-storage/src/main/java/org/lucares/pdb/map/PersistentMap.java
index ae757f3..58581f7 100644
--- a/block-storage/src/main/java/org/lucares/pdb/map/PersistentMap.java
+++ b/block-storage/src/main/java/org/lucares/pdb/map/PersistentMap.java
@@ -180,9 +180,9 @@ public class PersistentMap<K, V> implements AutoCloseable {
 
     private final EncoderDecoder<V> valueEncoder;
 
-    private final LRUCache<Long, PersistentMapDiskNode> nodeCache = new LRUCache<>(10_000);
+    private final LRUCache<Long, PersistentMapDiskNode> nodeCache = new LRUCache<>(500);
 
-    private final LRUCache<ByteArrayKey, V> valueCache = new LRUCache<>(10_000);
+    private final LRUCache<ByteArrayKey, V> valueCache = new LRUCache<>(1000);
 
     // guarded by: this
     private volatile long nodeOffsetOfRootNode = -1;