additional info re: Tungsten

Author: Ivan Groenewold

doc/cheatsheet.md

@@ -146,8 +146,12 @@ gh-ost --allow-master-master --assume-master-host=a.specific.master.com
 
 Topologies using _tungsten replicator_ are peculiar in that the participating servers are not actually aware they are replicating. The _tungsten replicator_ looks just like another app issuing queries on those hosts. `gh-ost` is unable to identify that a server participates in a _tungsten_ topology.
 
-If you choose to migrate directly on master (see above), there's nothing special you need to do. If you choose to migrate via replica, then you must supply the identity of the master, and indicate this is a tungsten setup, as follows:
+If you choose to migrate directly on master (see above), there's nothing special you need to do. 
+
+If you choose to migrate via replica, then you need to make sure Tungsten is configured with log-slave-updates parameter (note this is different from MySQL's own log-slave-updates parameter), otherwise changes will not be in the replica's binlog, causing data to be corrupted after table swap. You must also supply the identity of the master, and indicate this is a tungsten setup, as follows:
 
 ```
 gh-ost --tungsten --assume-master-host=the.topology.master.com
 ```
+
+Also note that `--switch-to-rbr` does not work for a Tungsten setup as the replication process is external, so you need to make sure `binlog_format` is set to ROW beforehand.