partitions for RAID volumes?

partitions for RAID volumes?

[rayn]

Hi,

Is there any chance that RAID volumes would support partitions like the
hard-disk driver in the future? This could be handsome if you try to
program a kernel driver for any of those RAID adapters (e.g. thinking of
those Fasttrack or Highpoint lowcost IDE controllers). A RAID
personality could take over all the controller specific stuff.
I have done this for the Highpoint HTP370, which is found on some of the
new ABIT mainboards. I am running a dualboot system (Win98/Linux) on one
RAID volume with two partitions (a swap partition is not supported on
raid devices). And LILO boots it! *joy*
I have created a patch for this which applies to kernel 2.2.18. This
does the partition trick and contains a mixture of the RAID-0 and RAID-1
code to do the disk striping (only disk striping is supported). So if
anyone is interrested in the patch contact me. But be aware that
installation is not a piece of cake!

Wilfried Weissmann

Re: partitions for RAID volumes?

[Neil Brown]

On Wednesday February 21, Wilfried.Weissmann@gmx.at wrote:
> Hi,
> 
> Is there any chance that RAID volumes would support partitions like the
> hard-disk driver in the future? 

Yep.
See: http://www.cse.unsw.edu.au/~neilb/patches/linux/2.4.2-pre4/

You would need patches H,I,N,O,P,Q,R,  and you should consider this a
very early release, but it works for me.
It uses a second major device number for partitioned md arrays. You
can only partition the first 16 arrays (md0 - md15) and only have 15
partitions per array.  It wont work well for raid5, but for raid1
(which is what I particularly want) or raid0 it should be fine.

Using this, I can RAID1 hda and hdc together as md0 == mda and then
partition it up as mda1 (root) mda2 (swap) mda3 (other).  And if I
have too, I can boot off either drive individually with any raid
happening.

Lilo needs to be hacked a bit to do the right thing, and I have got a
major number officially allocated from lanana, but as I said, this is
a very early release.

NeilBrown

Re: partitions for RAID volumes?

[rayn]

Jeremy Jackson wrote:
> 
> rayn wrote:
> 
> > Hi,
> >
> > Is there any chance that RAID volumes would support partitions like the
> > hard-disk driver in the future? This could be handsome if you try to
> 
> You may wish to try LVM in kernel 2.4.0.  This is much more flexible
> for administration, but I don't know about windoze...

I agree. I know LVM from HP-UX and it works absolutely flawless there.
But when it comes to dualbooting several OSes like Linux and Win* I do
not think that you have a chance with LVM (unless all OSes support the
same LVM standard. Microsoft pops in my mind!).

Wilfried Weissmann

Re: partitions for RAID volumes?

[Matt Stegman]

On Thu, 22 Feb 2001, Neil Brown wrote:

> On Wednesday February 21, Wilfried.Weissmann@gmx.at wrote:
> > Hi,
> > 
> > Is there any chance that RAID volumes would support partitions like the
> > hard-disk driver in the future? 
> 
> Yep.
> See: http://www.cse.unsw.edu.au/~neilb/patches/linux/2.4.2-pre4/
> 
> You would need patches H,I,N,O,P,Q,R,  and you should consider this a
> very early release, but it works for me.
> ...
> Using this, I can RAID1 hda and hdc together as md0 == mda and then
> partition it up as mda1 (root) mda2 (swap) mda3 (other).  And if I
> have too, I can boot off either drive individually with any raid
> happening.

Is there any particular reason to prefer this over LVM?  With 2.4, LVM can
be a layer atop of software RAID, allowing for multiple volumes, online
volume resizing, and other cool things.

-Matt Stegman
<mas9483@cis.ksu.edu>

Re: partitions for RAID volumes?

[Neil Brown]

On Wednesday February 21, mas9483@cis.ksu.edu wrote:
> On Thu, 22 Feb 2001, Neil Brown wrote:


Paragraph 1
> > Using this, I can RAID1 hda and hdc together as md0 == mda and then
> > partition it up as mda1 (root) mda2 (swap) mda3 (other).  And if I
> > have too, I can boot off either drive individually with any raid
> > happening.
> 

Paragraph 2
> Is there any particular reason to prefer this over LVM?  With 2.4, LVM can
> be a layer atop of software RAID, allowing for multiple volumes, online
> volume resizing, and other cool things.
> 
> -Matt Stegman
> <mas9483@cis.ksu.edu>
> 


Paragraph 1 is my answer to paragraph 2.

Also, I don't particularly want to use LVM.  Partitions work fine for
me.  I don't need to learn new tools.

It's about choice.

NeilBrown