diff --git a/etc/object-server.conf-sample b/etc/object-server.conf-sample
index c78ca2de5e..0e6b3cce5b 100644
--- a/etc/object-server.conf-sample
+++ b/etc/object-server.conf-sample
@@ -23,6 +23,8 @@ use = egg:swift#object
 # disk_chunk_size = 65536
 # max_upload_time = 86400
 # slow = 1
+# on PUTs, sync data every n MB
+# mb_per_sync = 512
 
 [object-replicator]
 # log_name = object-replicator
diff --git a/swift/obj/server.py b/swift/obj/server.py
index fe26eebf20..6a15aef35d 100644
--- a/swift/obj/server.py
+++ b/swift/obj/server.py
@@ -259,7 +259,7 @@ class ObjectController(object):
         self.log_requests = conf.get('log_requests', 't')[:1].lower() == 't'
         self.max_upload_time = int(conf.get('max_upload_time', 86400))
         self.slow = int(conf.get('slow', 0))
-        self.chunks_per_sync = int(conf.get('chunks_per_sync', 8000))
+        self.bytes_per_sync = int(conf.get('mb_per_sync', 512)) * 1024 * 1024
 
     def container_update(self, op, account, container, obj, headers_in,
                          headers_out, objdevice):
@@ -359,11 +359,10 @@ class ObjectController(object):
         upload_expiration = time.time() + self.max_upload_time
         etag = md5()
         upload_size = 0
+        last_sync = 0
         with file.mkstemp() as (fd, tmppath):
             if 'content-length' in request.headers:
                 fallocate(fd, int(request.headers['content-length']))
-            chunk_count = 0
-            dropped_cache = 0
             for chunk in iter(lambda: request.body_file.read(
                     self.network_chunk_size), ''):
                 upload_size += len(chunk)
@@ -373,13 +372,11 @@ class ObjectController(object):
                 while chunk:
                     written = os.write(fd, chunk)
                     chunk = chunk[written:]
-                chunk_count += 1
                 # For large files sync every 512MB (by default) written
-                if chunk_count % self.chunks_per_sync == 0:
+                if upload_size - last_sync >= self.bytes_per_sync:
                     os.fdatasync(fd)
-                    drop_buffer_cache(fd, dropped_cache,
-                        upload_size - dropped_cache)
-                    dropped_cache = upload_size
+                    drop_buffer_cache(fd, last_sync, upload_size - last_sync)
+                    last_sync = upload_size
 
             if 'content-length' in request.headers and \
                     int(request.headers['content-length']) != upload_size:
diff --git a/test/unit/obj/test_server.py b/test/unit/obj/test_server.py
index 048b409c63..94a3b28266 100644
--- a/test/unit/obj/test_server.py
+++ b/test/unit/obj/test_server.py
@@ -56,7 +56,7 @@ class TestObjectController(unittest.TestCase):
         mkdirs(os.path.join(self.testdir, 'sda1', 'tmp'))
         conf = {'devices': self.testdir, 'mount_check': 'false'}
         self.object_controller = object_server.ObjectController(conf)
-        self.object_controller.chunks_per_sync = 1
+        self.object_controller.bytes_per_sync = 1
 
     def tearDown(self):
         """ Tear down for testing swift.object_server.ObjectController """