Well, both parameters are different and have different usage. db_writer_processes will let you know how much db writer process are used for your I/O. filesystemio_options let you know you want to use async I/O or serial. If it's et for async and that is not supported by OS then oracle will probably make serial or initiate small process for I/O to simulate async effect. On Sun, Aug 16, 2009 at 12:08 AM, FreeLists Mailing List Manager < ecartis@xxxxxxxxxxxxx> wrote: > oracle-l Digest Sat, 15 Aug 2009 Volume: 06 Issue: 242 > > In This Issue: > db_writer_processes and Async IO ??? > > ---------------------------------------------------------------------- > > Date: Sat, 15 Aug 2009 15:36:28 -0700 (PDT) > From: dba1 mcc <mccdba1@xxxxxxxxx> > Subject: db_writer_processes and Async IO ??? > > we have ORACLE 10Gr2 on Redhar AS LInux server version 4.X. I checked one > of database init.ora have following setup: > > db_writer_processes = 2 > > filesystemio_options = asynch > DISK_ASYNCH_IO = true > TAPE_ASYNCH_IO = true > > Based on what I know "db_writer_processes " and "filesystemio_options = > asynch" are exclusive. Can anyone tell me database will use whiche one? > > Thanks. > > > > > ------------------------------ > > End of oracle-l Digest V6 #242 > ****************************** > > -- Thanks & Regards, Taral Desai Marie von Ebner-Eschenbach<http://www.brainyquote.com/quotes/authors/m/marie_von_ebnereschenbac.html> - "Even a stopped clock is right twice a day."