Hi,

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?

Thanks,
Grofaty

This is one of those parm you will need to test/test and test some more. On some of our boxes, most data wharehousing, it helped performace, on our oltp systems it hurt performace.

On the datawarehouse, was the improvement in performance quantifiable?

The reason I ask is we were asked to set it OFF on a DW. And from all that I've read, it should help. However we were on 1+0. If we move to 7+p, I would like to explore options.

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.