RonDB uses strict two-phase locking when using locks. READ COMMITTED is lockless and always reads the latest committed value. READ COMMITTED is default from MySQL.
Durability is attained through a REDO log, no UNDO logging is required since transactional state is kept in memory and persistent state is only changed at COMMIT both for in-memory and disk columns. The REDO log is logical, so only records the operations and its new values.
MySQL NDB Cluster