Hi John, Is the behaviour specific to exadata or that is fully/partially true in case of ASM too? Does any kind of background I/O queue exist on non-exadata but ASM (RAC/non-RAC) based env.? Thanks On Mon, Dec 31, 2012 at 7:31 AM, John Clarke <john.clarke@xxxxxxxxxxxx>wrote: > Redo log and control file writes are considered "high priority" I/O > consumers and get lumped into the high priority background I/O queue, so > cellsrv will satisfy these requests at a higher priority than anything else. > DBWR writes (which your db file parallel write waits is associated with) > are prioritized the same as user I/O, relatively speaking, and a handful of > other background-related writes and lower than log file/control file writes. > > Under heavy I/O load and saturation, this behavior should be what you may > expect. > > - John > > -- //www.freelists.org/webpage/oracle-l