Swap Space

Because Sun HPC applications are, on average, larger than those typically run on compute servers, the swap space allocated to Sun HPC clusters should be correspondingly larger. The amount of swap should be proportional to the number of CPUs and to the amount of installed memory. Additional swap should be configured to act as backing store for the shared memory communication areas used by Sun HPC ClusterTools 3.0 software in these situations.

Sun MPI jobs require large amounts of swap space for shared memory files. The sizes of shared memory files scale in stepwise fashion, rather than linearly. For example, a two-process job (with both processes running within the same SMP) requires shared memory files of approximately 35 Mbytes. A 16-process job (all processes running within the same SMP) requires shared memory files of approximately 85 Mbytes. A 256-process job (all processes running within the same SMP) requires shared memory files of approximately 210 Mbytes.