Using IBM's AIX dialect of UNIX, an I/O bound database server is usually evidenced by a high value in the wa (wait) column of vmstat. In the next listing, we see that 22 percent of the CPU time is being used waiting for database I/O.
It is important to note that a high wait value does not always signal an I/O bottleneck. The CPU wait could be due to other factors, and this metric simply means that the CPU is waiting for external OS services.
Now that we understand the basics of the vmstat utility, let's explore an easy method for capturing vmstat data, storing it inside an Oracle table, and producing server performance reports.
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