About

physical io (on the drive) is aimed to seed the buffer cache where the logical io (database logical) occurs.

Articles Related

How to handle excessive I/O waits?

There are several ways to handle excessive I/O waits. In the order of effectiveness, these are as follows:

• Reduce the I/O activity by SQL tuning
• Reduce the need to do I/O by managing the workload (in the time)
• Gather system statistics with DBMS_STATS package, allowing the query optimizer to accurately cost possible access paths that use full scans
• Use Automatic Storage Management
• Add more disks to reduce the number of I/Os for each disk
• Alleviate I/O hot spots by redistributing I/O across existing disks

Documentation / Reference

• Check IO Scripts (Manual querying AWR for trend analysis and capacity planning). Using services even on single instance, give the ablity to get trend information.