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 09a1aaf..4015d2f 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
@@ -12,10 +12,10 @@ import java.util.Stack;
 import java.util.UUID;
 
 import org.lucares.collections.LongList;
-import org.lucares.pdb.blockstorage.intsequence.VariableByteEncoder;
 import org.lucares.pdb.diskstorage.DiskBlock;
 import org.lucares.pdb.diskstorage.DiskStorage;
 import org.lucares.utils.Preconditions;
+import org.lucares.utils.byteencoder.VariableByteEncoder;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -24,7 +24,7 @@ public class PersistentMap<K, V> implements AutoCloseable {
 	private static final Logger LOGGER = LoggerFactory.getLogger(PersistentMap.class);
 
 	// the maximum key
-	private static final byte[] MAX_KEY;
+	static final byte[] MAX_KEY;
 	static {
 		MAX_KEY = new byte[20];
 		Arrays.fill(MAX_KEY, Byte.MAX_VALUE);
@@ -308,7 +308,7 @@ public class PersistentMap<K, V> implements AutoCloseable {
 		final byte[] newBuffer = node.serialize();
 		System.arraycopy(newBuffer, 0, buffer, 0, buffer.length);
 		diskBlock.writeAsync();
-		diskBlock.force();
+		// diskBlock.force(); // makes writing nodes slower by factor 800 (sic!)
 	}
 
 	public synchronized void print() throws IOException {