SAP Configuration Notes
We recommend the following parameters in your SAP profile so that extended memory and all other buffers use ISM
es/use_shared_memory = true
ipc/sem_fast_watchdog = 0
If "es/use_shared_memory" is not set, the extended memory will be allocated on anon memory and could be on a smaller page size if not aligned.
ISM is used for buffer management and extended memory starting with SAP 640 and 700 release. Older releases use regular shared memory instead of "ISM".
Configure a sufficient number of dialogue processes and update processes to ensure enqueue length is less than 5 on average.
Multiple instances of SAP may be required to achieve scaling. On high throughput workloads we have used 4 SAP instances on an 8 core Sun Fire CoolThreads sever.
Always check SAP R/3 buffer stats to make sure there is no swapping.
