add a comment about C* config
@@ -10,6 +10,14 @@ Scalar DB v1 is written in Java and uses Cassandra as an underlining storage imp
* [Oracle JDK 8](https://www.oracle.com/technetwork/java/javase/downloads/jdk8-downloads-2133151.html) (OpenJDK 8) or higher
* [Casssandra](http://cassandra.apache.org/) 3.11.x (the current stable version as of writing)
* Take a look at [this document](http://cassandra.apache.org/download/) for how to set up Cassandra.
+ * Change `commitlog_sync` from `periodic` to `batch` in `cassandra.yaml`
+```yaml:cassandra.yaml
+commitlog_sync: batch
+commitlog_sync_batch_window_in_ms: 2
+
+# commitlog_sync: periodic
+# commitlog_sync_period_in_ms: 10000
+```
* Other libraries used from the above are automatically installed through gradle
In addition to the above, the following software is needed to use schema tools.
