IDE performance question

IDE performance question

[Andrew Walrond]

I've got two 120Gb ide drives which I want to raid0 for performance, and my 
m/b has two IDE buses built in.

The linux-raid howto suggests putting one drive on each bus, because slave 
disks spoil performance.

Thats fine, I've got the usual two buses, but my question is: 

	Where should I put the CDROM drive?

Is the very existence of a slave device the source of the performance 
degredation, or just that the bandwidth has to be shared between the devices 
(so not a problem unless the cdrom is being accessed)?

Also, I remember from years ago that the cdrom could pull the whole bus down 
to some lower performance level (even if still using and 80wire cable?). Is 
this still the case? (The hardware in question is recent).

Knowledgeable advice sought :)

Andrew Walrond

Re: IDE performance question

[Gordon Henderson]

On Sun, 8 Aug 2004, Andrew Walrond wrote:

> I've got two 120Gb ide drives which I want to raid0 for performance, and
> my m/b has two IDE buses built in.
>
> The linux-raid howto suggests putting one drive on each bus, because
> slave disks spoil performance.

>
> Thats fine, I've got the usual two buses, but my question is:
>
> 	Where should I put the CDROM drive?

Just make it a slave on one of the buses.

> Is the very existence of a slave device the source of the performance
> degredation, or just that the bandwidth has to be shared between the devices
> (so not a problem unless the cdrom is being accessed)?

It won't be a problem uless you access it, and even then, as it's so slow
compared to the IDE drive (assumimng everything is DMA then it'll be just
fine)

> Also, I remember from years ago that the cdrom could pull the whole bus
> down to some lower performance level (even if still using and 80wire
> cable?). Is this still the case? (The hardware in question is recent).

It shouldn't be a problem with modern hardware.

Gordon
Ps. Familiar name ...