Solution : https://service.sap.com/sap/support/notes/793113 (SAP Service marketplace login required)
Summary :
This SAP Note discusses I/O configuration, emphasizing the arrangement of Oracle database files and settings on both the operating system and Oracle to optimize I/O behavior. Good I/O configurations eliminate bottlenecks and enhance resource efficiency, thus improving database performance. Recommendations for Oracle’s disk layout include separate areas for redo logs and data files and avoiding conventional RAID 5 for redo logs. The note elaborates on mechanisms like file system cache, file lock, and cache synchronization that affect I/O operations in operating systems. It contrasts synchronous, asynchronous, cached, direct, concurrent, and raw I/O methods, noting their benefits and performances. Raw devices offer the best performance by sidestepping typical operating system mechanisms. The note also covers operating system-specific activation of asynchronous I/O and Oracle parameters influencing I/O methods, pointing out that parameters like DISK_ASYNCH_IO and FILESYSTEMIO_OPTIONS determine the use of asynchronous versus synchronous I/O.
Key words :
terms frequently asked questions solution 1, /oracle/p01/sapdata1/es620d_1/es620d, tuning processing-intensive sql statements, tpo storage subsystem optimization service, activate operating-system-dependent async, subsystem operating system parameter settings, lio_listio returned eagainperformance degradation, tune processing-intensive sortings, configured aio server processes, db file sequential read
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