Determining if Disks Are the Bottleneck

1. Use iostat to determine disk usage.

   Look at the number of read and write operations per second (see "Checking the NFS Server"" in Chapter 3, Analyzing NFS Performance).

Because there is little dependence in the stream of NFS requests, the disk activity generated contains large numbers of random access disk operations. The maximum number of random I/O operations per second ranges from 40-90 per disk.

Driving a single disk at more than 60 percent of its random I/O capacity creates a disk bottleneck.