[ltp] raid1 on thinkpad A31

[Andy Firman]

On Tue, Feb 17, 2004 at 06:40:58PM +0100, Ferdinand Haselbacher (jr.) wrote:
> On Tue, Feb 17, 2004 at 11:55:18AM -0500, Andy Firman wrote:
> > 
<snip>  
> > For a proper RAID1 mirror, it is best to have the 2 drives
> > on different controllers.  If they are both on the same
> > controller, and that controller dies, you can't boot.
> you can't see the controller as two separated chips ! they have two different
> irq's but they are in the same enclosure ! so if one controller dies it's very
> likely that the second one is also dead ! The only thing why you should put
> the disks on different controllers is because of the data transfer rate ! so
> you can write simultniously to both harddrives with "full" ide bus speed. 
> especially for RAID I it is very helpfull if they are on two sperated
> controllers because they are writing simultniously the same on both disks.

That is another consideration for separate controllers.  Thanks.

> > I have no idea what the controllers are like on a 
> > Thinkpad motherboard and assume there is no /dev/hdd.
> > 
> > Are hda, hdb, and hdc all on the same controller?
> > 
> > Any other comments on my Thinkpad RAID1 project are welcome.
> For what the hell do u need raid on an notebook ? don't you pay a very high
> price for redundancy ? wouldn't it be easier if u just use intermezzo fs to
> sync your files daily with a home located data server !? IMHO this would be
> much more inexpensive, and if u don't know what to do with your second 2,5"
> hd built a car MP3-Player :-) 

I hear ya.  But I am doing this for practice on bringing up existing 
systems to root on raid.  Also it is a good piece of mind.  And I have
an extra 40GB drive and I might as well put it to use.

Andy