Sun Java System Application Server Enterprise Edition 8.1 2005Q2 Performance Tuning Guide

- Previous: Network Interface
- Next: TCP/IP Settings

## To tune disk I/O performance for non SCSI disks

1. Test the disk speed.

   Use this command:

       /sbin/hdparm -t /dev/hdX

2. Enable direct memory access (DMA).

   Use 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.

   For information on SCSI disks, see: System Tuning for Linux Servers — SCSI.

- Previous: Network Interface
- Next: TCP/IP Settings

- © 2010, Oracle Corporation and/or its affiliates