Tuning the Storage Subsystem - Expert Oracle RAC Performance Diagnostics and Tuning - page 375

Figure 12-11 illustrates performance statistics for this view through OEM. Historical I/O statistics from this view
are captured in three separate views:

•

DBA_HIST_IOSTAT_DETAIL — This view displays I/O statistics aggregated by combination of file
type and function.

•

DBA_HIST_IOSTAT_FILETYPE — This view displays I/O statistics by file type. Statistics from file
types like flashback log, control file, temp file, data file, and so on are contained in this view.

•

DBA_HIST_IOSTAT_FUNCTION — This view displays I/O statistics by function. Statistics from
functions like Recovery, Buffer Cache Reads, RMAN, Data Pump, LGWR , DBWR , and so forth are
contained in this view.

Figure 12-11. OEM - I/O statistics for all disks in the diskgroup

Enterprise Manager to Monitor Storage
Enterprise Manager is a good way to look at the performance of disks and diskgroups in ASM. Once the ASM targets
are discovered, OEM provides performance charts at the diskgroup level; those charts can be drilled down to the disk
level. Figure 12-12 displays I/O performance statistics for the various diskgroups used by ASM-supported
databases (clients) on the server.