Unanswered: Performance question: RAID-5 and DB2_PARALLEL_IO setting
On DB2 Magazine I have found some tip about setting DB2_PARALLEL_IO environment variable if RAID-5 are used. My system is Intel box, Windows XP, DB2 v7.2 fp5 and data are stored to Enterprise Storage Server (RAID-5 system).
Question: Will DB2_PARALLEL_IO=* setting reduce I/O operations and so improve performance? Any experience?
We saw about a 10% improvement on 1 of them. Others received no improvment or negative improvement. I really feel it has something to do with our hardward, they are all different type of servers. But you will need to test like I said, Our OLTP systems had mixed results with some getting a -25-50% improvement.