Oracle Database Tunning Harddisk (I O)

• DBW (Database Base Writer) 
• V$SYSTEM_EVENT , TOTAL_WAITS is high
• the tuning goal for disk I/O performance is to balance I/O and reduce I/O contention. 
• keep heavily used file separate from each other. 
• keep non-Oracle files on disks separate from Oracle files. 
• use Hardware Raid
• do not place nonsystem object in the System Tablespace. 
• use temporary tablespace for sort segments
• keep table and index segments in separate tablespace
• use locally managed tablespace to reduce system tablespace I/O and fragmentation
• set the DB_FILE_MULTIBLOCK_READ_COUNT parameter to improve I/O where performing full table scans. (FTSs) 
• Redo log file should be sized large enough so that redo log switchs do not happen so often that performance is affect.
• Redo log files should be kept on separate fast devices. 
• if the ARCn process cannot keep up the archiving requirement, you can specify additional ARCn processes by setting the LOG_ARCHIVE_MAX_PROCESSES parameter to a value between 1 and 10.