Web Hosting Talk : Web Hosting Main Forums : Hosting Security and Technology : How to enable DMA on CentOS

[RackPoint-Morgan]

Hey how would I go about enabling DMA on a SATA hard drive in centOS 4.2? I did this a couple months ago but I forgot how and I need to do it again :/. Thanks!

[almahdi]

Using CPANEL?

If yes, use /scripts/hdparmon

Other wise, you have to use hdparm to set DMA modes..

Note: I believe Kernel 2.6 enables DMA by default.

[RackPoint-Morgan]

I ran /scripts/hdparmon and I am also running the 2.6.x kernel. I am not seeing anything about DMA with a df or in cpanel, how do I double check. I know theres an individual command to check the HD.

[almahdi]

In kernel 2.6 DMA is enabled by default..


df is to check how much space left/used on your disk ( not DMA )..

However, in WHM, if you go to Server Infomation, You'll find Physical Disks, and see if UDMA is there or not..

Or use hdparm -i /dev/hda

and find out if you have DMA enabled.

[RackPoint-Morgan]

[root@ds100101 /]# hdparm -i /dev/sda

/dev/sda:
HDIO_GET_IDENTITY failed: Inappropriate ioctl for device

[PerfTuner]

Most likely it's already configured properly.
Do
hdparm -tT /dev/sda
Should give you about 50-60 megs/second for unbuffered reads.

[Cirrostratus]

Originally Posted by Netriox

[root@ds100101 /]# hdparm -i /dev/sda

/dev/sda:
HDIO_GET_IDENTITY failed: Inappropriate ioctl for device

hdparm only works on IDE / ATA devices and will show that error with SCSI or SATA devices.

Thanks,

Jeremy