Re: Debian+LVM+RAID

[lee <lee@yun.yagibdah.de>]

On Thu, Jul 09, 2009 at 11:42:16AM +0200, martin f krafft wrote:
> also sprach lee <lee@yun.yagibdah.de> [2009.07.09.0707 +0200]:
> > Why do you need LVM?
> 
> LVM offers features that RAID does not. If you want those features,
> you need LVM.

Yeah, but that wasn't what I was asking. I tried to find out what
features he needed and what he's trying to do.

> > The RAID array must be partitionable, which is an option you
> > eventually need to specify when creating it. I don't know what the
> [...]
> > To clarify: There are partitionable RAID arrays and
> > non-partitionable RAID arrays. When creating a RAID array, you
> > need to specify which kind --- partitionable or non-partitionable
> > --- you want to create.
> 
> Since 2.6.29, all RAIDs are partitionable. Not in lenny though.

See man madadm:


"
       -a, --auto{=no,yes,md,mdp,part,p}{NN}
              Instruct mdadm to create the device file if needed,
              possibly allocating an unused minor number.  "md" causes
              a non-partitionable array to be used.  "mdp", "part" or
              "p" causes a partitionable array (2.6 and later) to be
              used.
"

You can still decide if you want a partitionable or non-partitionable
RAID, thus not all RAIDs are partitionable since kernel
2.6.29. Unfortunately, the man page doesn't seem to say what the
default is for the partitionability of the RAID.