Sun Java System Access Manager 7.1 Performance Tuning and Troubleshooting Guide

Disk I/O Settings

To tune disk I/O performance for a non-SCSI disk, follow these steps:

  1. Test the disk speed with this command:

     /sbin/hdparm -t /dev/hdX
  2. Enable direct memory access (DMA) with this command:

    /sbin/hdparm -d1 /dev/hdX
  3. Check the speed again using the hdparm command. Given that DMA is not enabled by default, the transfer rate might have improved considerably. In order to do this at every reboot, add the /sbin/hdparm -d1 /dev/hdX line to /etc/conf.d/local.start, /etc/init.d/rc.local, or whatever the startup script is called.