[nzlug] General software RAID1 query

[Warren Boyd]

On 2006-10-06, at 11:50 , Roland Hill wrote:

> Hi,
>
> I've configured software RAID1 on a kubuntu box.
>
> It's just 2 IDE HDD's in the array, and I put both HDD's on the  
> primary
> IDE channel.
>
> It's bugged me every since, but would I get better read/write
> performance if the HDD's were on separate IDE channels?
>

You should definitely get better performance - iirc the channels  
"share" bandwidth between the devices on it.

> If so, how hard is it to rebuild the array once I have moved the  
> primary
> slave to the secondary master position.
>
> (sorry RAID newbie here - all pointers to reading the *fine* manual
> accepted!)

Back up FIRST!

You should be able to put the secondary/slave ide into 'offline' or  
down graded mode, alter the md config files power down.  Change the  
drive onto the primary elsewhere and then power up.

 From how I remember it has changed, the MD tools have the ability to  
auto-detect magically the details of the raid set(s) and configure  
them appropriately - so you may not even have to alter config files  
for this to happen.

I would certainly google for more detail on RAID1 / MD tools before  
attempting.  (unless your a masochist and desire a little bit of a  
challenge.  Although backup first.)

HTH,
Warren.