DASD Performance

DASD performance problems don’t go away with the newer technologies such as Symmetrix, RAMAC, ICEBERG, other RAID devices. You need even more knowledge to do the job correctly.
As an example, lets take our new whiz-bang dasd that has 4-Gigabyte or 8-Gigabyte drives inside. Each of these is chopped up into multiple logical 3390 devices.
SO…. you think you are doing a good job separating you heavily accessed objects, or separating your indexes from data by using DB2BBB and DB2FFF. However, they map to the same physical device internally.
Viola…. performance problems!!!

Granted this is an over simplification, but you should get the general idea…..