diff --git a/hbs2-storage-ncq/hbs2-storage-ncq.cabal b/hbs2-storage-ncq/hbs2-storage-ncq.cabal
index f851dfd8..690aad9e 100644
--- a/hbs2-storage-ncq/hbs2-storage-ncq.cabal
+++ b/hbs2-storage-ncq/hbs2-storage-ncq.cabal
@@ -74,6 +74,7 @@ library
       HBS2.Storage.NCQ3.Internal.Files
       HBS2.Storage.NCQ3.Internal.Fossil
       HBS2.Storage.NCQ3.Internal.Flags
+      HBS2.Storage.NCQ3.Internal.Fsync
       HBS2.Storage.NCQ
       HBS2.Storage.NCQ.Types
     -- other-modules:
diff --git a/hbs2-storage-ncq/lib/HBS2/Storage/NCQ3/Internal/Fsync.hs b/hbs2-storage-ncq/lib/HBS2/Storage/NCQ3/Internal/Fsync.hs
new file mode 100644
index 00000000..6dbd7765
--- /dev/null
+++ b/hbs2-storage-ncq/lib/HBS2/Storage/NCQ3/Internal/Fsync.hs
@@ -0,0 +1,30 @@
+{-# LANGUAGE ForeignFunctionInterface #-}
+{-# LANGUAGE CApiFFI #-}
+{-# LANGUAGE CPP #-}
+module HBS2.Storage.NCQ3.Internal.Fsync where
+
+import Foreign.C.Types
+import System.Posix.Types
+import System.Posix.Unistd (fileSynchronise)
+
+foreign import capi unsafe "unistd.h fsync"
+  c_fsync :: CInt -> IO CInt
+
+#if defined(darwin_HOST_OS)
+foreign import capi unsafe "fcntl.h fcntl"
+  c_fcntl :: CInt -> CInt -> CInt -> IO CInt
+
+foreign import capi unsafe "fcntl.h value F_FULLFSYNC"
+  f_FULLFSYNC :: CInt
+#endif
+
+fileSynchronisePortable :: Fd -> IO ()
+fileSynchronisePortable fd@(Fd fdi) = do
+#if defined(darwin_HOST_OS)
+  c_fcntl fdi f_FULLFSYNC 0
+#else
+  fileSynchronise fd
+#endif
+{-# INLINE fileSynchronisePortable #-}
+
+
diff --git a/hbs2-storage-ncq/lib/HBS2/Storage/NCQ3/Internal/Run.hs b/hbs2-storage-ncq/lib/HBS2/Storage/NCQ3/Internal/Run.hs
index a840bc1d..cecae900 100644
--- a/hbs2-storage-ncq/lib/HBS2/Storage/NCQ3/Internal/Run.hs
+++ b/hbs2-storage-ncq/lib/HBS2/Storage/NCQ3/Internal/Run.hs
@@ -12,6 +12,7 @@ import HBS2.Storage.NCQ3.Internal.Sweep
 import HBS2.Storage.NCQ3.Internal.MMapCache
 import HBS2.Storage.NCQ3.Internal.Fossil
 import HBS2.Storage.NCQ3.Internal.Flags
+import HBS2.Storage.NCQ3.Internal.Fsync
 
 import Control.Concurrent.STM qualified as STM
 import Control.Monad.Trans.Cont
@@ -31,6 +32,8 @@ import System.Posix.IO.ByteString as Posix
 import System.Posix.Types as Posix
 import System.Posix.Unistd
 
+{- HLINT ignore "Eta reduce" -}
+
 ncqStorageStop :: forall m . MonadUnliftIO m => NCQStorage -> m ()
 ncqStorageStop NCQStorage{..} = do
   atomically $ writeTVar ncqStopReq True
@@ -267,7 +270,7 @@ ncqStorageRun ncq@NCQStorage{..} = withSem ncqRunSem $ flip runContT pure do
                 else do
 
                   ss <- appendTailSection fh
-                  liftIO (fileSynchronise fh)
+                  liftIO (fileSynchronisePortable fh)
 
                   -- ss <- liftIO (PFS.getFdStatus fh) <&> fromIntegral . PFS.fileSize