diff --git a/config b/config
index a0922b36..1cdfb75a 100644
--- a/config
+++ b/config
@@ -103,6 +103,11 @@
 # Folder for storing local collections, created if not present
 #filesystem_folder = ~/.config/radicale/collections
 
+# Sync all changes to disk during requests. (This can impair performance.)
+# Disabling it increases the risk of data loss, when the system crashes or
+# power fails!
+#fsync = True
+
 # Command that is run after changes to storage
 #hook =
 # Example: git add -A && (git diff --cached --quiet || git commit -m "Changes by "%(user)s)
diff --git a/radicale/config.py b/radicale/config.py
index 980cf78c..1e02656d 100644
--- a/radicale/config.py
+++ b/radicale/config.py
@@ -58,6 +58,7 @@ INITIAL_CONFIG = {
         "type": "multifilesystem",
         "filesystem_folder": os.path.expanduser(
             "~/.config/radicale/collections"),
+        "fsync": "True",
         "hook": ""},
     "logging": {
         "config": "/etc/radicale/logging",
diff --git a/radicale/storage.py b/radicale/storage.py
index 06b2905c..9542ad6b 100644
--- a/radicale/storage.py
+++ b/radicale/storage.py
@@ -393,10 +393,11 @@ class Collection(BaseCollection):
                                  delete=False, prefix=".Radicale.tmp-")
         try:
             yield tmp
-            if os.name == "posix" and hasattr(fcntl, "F_FULLFSYNC"):
-                fcntl.fcntl(tmp.fileno(), fcntl.F_FULLFSYNC)
-            else:
-                os.fsync(tmp.fileno())
+            if self.configuration.getboolean("storage", "fsync"):
+                if os.name == "posix" and hasattr(fcntl, "F_FULLFSYNC"):
+                    fcntl.fcntl(tmp.fileno(), fcntl.F_FULLFSYNC)
+                else:
+                    os.fsync(tmp.fileno())
             tmp.close()
             os.rename(tmp.name, path)
         except:
@@ -413,13 +414,15 @@ class Collection(BaseCollection):
                 return file_name
         raise FileExistsError(errno.EEXIST, "No usable file name found")
 
-    @staticmethod
-    def _sync_directory(path):
+    @classmethod
+    def _sync_directory(cls, path):
         """Sync directory to disk.
 
         This only works on POSIX and does nothing on other systems.
 
         """
+        if not cls.configuration.getboolean("storage", "fsync"):
+            return
         if os.name == "posix":
             fd = os.open(path, 0)
             try: