How to removing or reduce the size of redo logs in MySQL cluster
You can decrease the size of redo log files by decreasing parameter NoOfFragmentLogFiles which defines no. of fragment files or by reducing size of each fragment file by parameter FragmentLogFileSize. By default  NoOfFragmentLogFiles=16 and FragmentLogFileSize=16M. Hence total redo log files size will be 256MB and there are 4 of these if you will look into your file directory system; D8 D9 D10 D11; If your NoOfReplicas parameter is 1 then only one redo log file will take upto size 256MB and rest will have an apparent size of 256MB not actual.You can see the redo usage by executing command all dump 2398; on management node and look into node's ndb_"NODEID"_out.log. You will see redo files usage.