debian里面开启dma功能,提高硬盘读写速度

1.安装hdparm
[code]debian:~#aptitude install hdparm[/code]
手动起动DMA：
[code]debian:~#hdparm -d1 /dev/hda[/code]

2.配制系统起动时自动打开磁盘DMA
A.在 /etc/init.d/ 目录下新建文件dma-start.sh 内容如下：

[code]#!/bin/sh
#This script start ATA100 DMA
hdparm -d1 /dev/hda[/code]

B.在/etc/rc2.d/下建一个连接到刚才建的文件
[code]debian:~#ln -s /etc/init.d/dma-start.sh /etc/rc2.d/S95dma-start.sh[/code]
3.对比
[code]debian:~# hdparm -d0 /dev/hda[/code]
/dev/hda:
setting using_dma to 0 (off)
using_dma = 0 (off)

[code]debian:~# hdparm -t /dev/hda[/code]
/dev/hda: Timing buffered
disk reads: 12 MB in 3.33 seconds = 3.61 MB/sec

[code]debian:~# hdparm -d1 /dev/hda[/code]
/dev/hda:
setting using_dma to 1 (on)
using_dma = 1 (on)

[code]debian:~#hdparm -t /dev/hda[/code]
/dev/hda: Timing buffered
disk reads: 156 MB in 3.01 seconds = 51.89 MB/sec