diff --git a/src/lib/utils/rotatefile.cpp b/src/lib/utils/rotatefile.cpp
index 0133b61f..af24c3f0 100644
--- a/src/lib/utils/rotatefile.cpp
+++ b/src/lib/utils/rotatefile.cpp
@@ -71,17 +71,21 @@ void RotateFile::write(const unsigned char* value, const size_t size, const bool
       for (unsigned int pos = 0; pos < size; pos++) {
         fprintf(m_stream, "%2.2x ", value[pos]);
       }
+      m_fileSize += 25+3*size+1;
     } else {
       fwrite(value, 1, size, m_stream);
+      m_fileSize += size+1;
     }
     fprintf(m_stream, "\n");
-    m_fileSize += 25+3*size+1;
+    fflush(m_stream);
   } else {
     fwrite(value, (streamsize)size, 1, m_stream);
     m_fileSize += size;
-  }
-  if ((m_fileSize%1024) == 0) {
-    fflush(m_stream);
+    m_flushSize += size;
+    if (m_flushSize>16) {
+      fflush(m_stream);
+      m_flushSize = 0;
+    }
   }
   if (m_fileSize >= m_maxSize * 1024LL) {
     string oldfile = string(m_fileName)+".old";
diff --git a/src/lib/utils/rotatefile.h b/src/lib/utils/rotatefile.h
index ee111bf6..67df2a23 100644
--- a/src/lib/utils/rotatefile.h
+++ b/src/lib/utils/rotatefile.h
@@ -45,7 +45,8 @@ class RotateFile {
    * @param textMode whether to write each byte with prefixed timestamp and direction as text.
    */
   RotateFile(const string fileName, const unsigned int maxSize, const bool textMode = false)
-    : m_enabled(false), m_fileName(fileName), m_maxSize(maxSize), m_textMode(textMode), m_stream(), m_fileSize(0) {}
+    : m_enabled(false), m_fileName(fileName), m_maxSize(maxSize), m_textMode(textMode), m_stream(), m_fileSize(0),
+      m_flushSize(0) {}
 
   /**
    * Destructor.
@@ -92,8 +93,11 @@ class RotateFile {
   /** the @a FILE to writing to. */
   FILE* m_stream;
 
-  /** the number of bytes already written to the @a m_file. */
+  /** the number of bytes written to @a m_file. */
   uint64_t m_fileSize;
+
+  /** the number of bytes written to @a m_file since the last flush. */
+  uint64_t m_flushSize;
 };
 
 }  // namespace ebusd