setting dma mode using hdparm?

[inetd]

I have two 80G harddrives with 7200RPM on RH7.3 linux. I want to tune them to use dma by using hdparm but it fails:

[root@linux02 root]# hdparm -Tt /dev/hda

/dev/hda:
Timing buffer-cache reads: 128 MB in 0.36 seconds =355.56 MB/sec
Timing buffered disk reads: 64 MB in 20.64 seconds = 3.10 MB/sec

[root@linux02 root]# hdparm -d1 /dev/hda

/dev/hda:
setting using_dma to 1 (on)
HDIO_SET_DMA failed: Operation not permitted
using_dma = 0 (off)


The disk reads (3.10 MB/sec) is really slow.

How can I tune it?

Thanks.

 

[fluid11]

Lets see the output of 'hdparm /dev/hda'.


'hdparm -d1 -X66 /dev/hda' - the d1 option is used to enable DMA mode. The X option is normally used with d1 to set the IDE transfer mode. This option is usually not necessary since most modern drives will detect and set this automatically. Be careful when setting this option!


ChrisP