Tuning I/O Subsystem: A Key Component in RDBMS Performance Tuning

In a computer system, the fastest storage component is the CPU cache, followed by the system memory. I/O to disk is thousands of times slower than an access to memory. This fact is the key for why you try to make effective use of memory whenever possible and defer I/Os whenever you can. The majority of the user response time is actually spent waiting for a disk I/O to occur. By making good use of caches in memory and reducing I/O overhead, you can optimize performance. The goal is to retrieve data from memory whenever you can and to use the CPU for other activities whenever you have to wait for I/Os. This paper examines ways to optimize the performance of the system by taking advantage of caching and effective use of the system's CPUs.