[CentOS] Re: DMA mode

Tom G. Christensen tgc at statsbiblioteket.dk
Tue Jun 3 08:17:14 UTC 2008

David Mackintosh wrote:
> Hi folks,
> I have an HP Proliant 140DL G2 server with what appears to be an IDE
> drive in non-DMA mode.  Performance on the server is extremely bad
> when large amounts of disk activity is taking place.
> I think the problem is that my drive is not in DMA mode:
> # hdparm /dev/hda
This should be /dev/sda and not /dev/hda which means you're most likely 
using the generic-ide driver and not ata-piix.

Google suggests booting with ide0=noprobe ide1=noprobe to make sure the 
ata-piix driver is used.
If you don't want to reinstall then make sure initrd contains the 
ata-piix driver and that references to /dev/hd* are replaced with 
/dev/sd* in fstab etc.


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