NDB Cluster Configuration Files This parameter determines whether Non-Uniform Memory Access (NUMA) is controlled by the operating system or by the data node process, whether the data node uses  ndbd  or  ndbmtd . By default,  NDB attempts to use an interleaved NUMA memory allocation policy on any data node where the host operating system provides NUMA support. Setting  Numa = 0  means that the datanode process does not itself attempt to set a policy for memory allocation, and permits this behavior to be determined by the operating system, which may be further guided by the separate  numactl  tool. That is,  Numa = 0  yields the system default behavior, which can be customised by  numactl . For many Linux systems, the system default behavior is to allocate socket- local memory to any given process at allocation time. This can be problematic when using  ndbmtd ; this is because  nbdmtd  allocates all memory at startup, leading to an imbalance, giving different access speeds for different sockets, especially when locking pages in main memory. Setting  Numa = 1  means that the data node process uses  libnuma  to request interleaved memory allocation. (This can also be accomplished manually, on the operating system level, using  numactl .) Using interleaved allocation in effect tells the data node process to ignore non-uniform memory access but does not attempt to take any advantage of fast local memory; instead, the data node process tries to avoid imbalances due to slow remote memory. If interleaved allocation is not desired, set  Numa  to 0 so that the desired behavior can be determined on the operating system level. The  Numa  configuration parameter is supported only on Linux systems where  libnuma.so  is available. Setting this parameter to 1 enables real-time scheduling of data node threads. The default is 0 (scheduling disabled). 4125 Version (or later) NDB 8.0.13 Type or units µs Default 50 Range 0 - 11000 Version (or later) NDB 8.0.13 Type or units boolean Default false Range true, false Restart Type N (NDB 8.0.13) Version (or later) NDB 8.0.13 Type or units numeric Default 1 Range ... Restart Type N (NDB 8.0.13) • Numa • RealtimeScheduler • SchedulerExecutionTimer