Re: Strange system behaviour when copying disks

[Olaf Frączyk <olaf@xxxxxxxxxxxxx>]

On Wed, 2003-05-14 at 17:21, Walt H wrote:

> 
> Do you have dma enabled on your IDE disks? I can't think of any reason
> off the top of my head why a cat from hda -> hdc should be affected by
> XFS, as you aren't using the filesystem for that - it's just reading the
> raw device. 
Yes, I know. I just don't know if XFS code changes some buffering etc.
Maybe with vanilla kernel it would be the same. I just have no easy way
to test it.
Make sure dma is enabled on hda and hdc and see if that
> helps:  hdparm -d1 /dev/hda /dev/hdc
> 
Both drives have dma enabled.
And they are set to UDMA-100 also.

I'm just curious where from comes this terrible latency.

Regards,

Olaf