diff --git a/performanceDb/src/main/java/org/lucares/performance/db/PdbWriter.java b/performanceDb/src/main/java/org/lucares/performance/db/PdbWriter.java
index 49e2c41..378f31b 100644
--- a/performanceDb/src/main/java/org/lucares/performance/db/PdbWriter.java
+++ b/performanceDb/src/main/java/org/lucares/performance/db/PdbWriter.java
@@ -4,9 +4,12 @@ import java.io.BufferedOutputStream;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
+import java.util.logging.Logger;
 
 class PdbWriter implements AutoCloseable {
 
+	private final static Logger LOGGER = Logger.getLogger(PdbWriter.class.getCanonicalName());
+
 	private static final boolean APPEND = true;
 	private final OutputStream outputStream;
 	private final PdbFile pdbFile;
@@ -29,10 +32,11 @@ class PdbWriter implements AutoCloseable {
 	}
 
 	public void write(final Entry entry) throws WriteException {
+		// System.out.println(entry);
 		write(entry.getEpochMilli(), entry.getValue());
 	}
 
-	void write(final long epochMilli, final long value) throws WriteException {
+	private void write(final long epochMilli, final long value) throws WriteException {
 		final long offsetEpochMilli = pdbFile.getOffsetInEpochMilli();
 		final long adjustedValue = epochMilli - offsetEpochMilli;
 		assertValueInRange(adjustedValue);
@@ -46,7 +50,10 @@ class PdbWriter implements AutoCloseable {
 
 	private void assertEpochMilliInRange(final long epochMilli) {
 		if (epochMilli < minimalEpochMilli) {
-			throw new IllegalArgumentException("value must not be smaller than: " + minimalEpochMilli);
+			LOGGER.warning("epochMilli must not be smaller than " + minimalEpochMilli + ", but was " + epochMilli
+					+ ". We'll accept this for now. "
+					+ "Currently there is no code that relies on monotonically increasing date values. "
+					+ "Log4j does not guarantee it either.");
 		}
 	}