Re: [gentoo-user] How to get raid

[Volker Armin Hemmann <volkerarmin@googlemail.com>]

Am Donnerstag, 5. Januar 2012, 20:13:04 schrieb Jeff Cranmer:
> On Thu, 2012-01-05 at 11:22 +0100, Volker Armin Hemmann wrote:
> > Am Mittwoch, 4. Januar 2012, 22:45:45 schrieb Jeff Cranmer:
> > > On Thu, 2012-01-05 at 04:01 +0100, Volker Armin Hemmann wrote:
> > > > the short one:
> > > > 
> > > > partition one disk with (c)fdisk. Use sfdisk to transfer the partition
> > > > scheme to the other disks.
> > > > 
> > > > run mdadm --create /dev/md0 level=whatever you want --raid-
> > > > devices=thenumberofdevices /dev/sdXY /dev/sdZY ...
> > > > 
> > > > mdadm --detail --scan >> /etc/mdadm.conf
> > > > 
> > > > done
> > > 
> > > OK, but there is active data on the disks, so I don't want to partition
> > > them.  They should already partitioned, and running fdisk will erase the
> > > data.
> > 
> > first rule:
> > 
> > always mount a scratch monkey
> > 
> > In your case: always backup data.
> 
> No big deal.
> 99.9% of the data is backed up.  I was just hoping to recover the last
> 0.1% (picky huh?<g>).  Now that I know one of the main drawbacks of
> fakeraid, I think I'll move ahead with software RAID.
> 
> OK, so I've partitioned the first disk as a single linux partition
> (/dev/sdb1, ID 83, Linux).

if you want to use kernel autodetection (nice but on the way out) you should 
change the type.

> How do I use sfdisk to transfer that partition scheme to the other
> disks?  Is it not sufficient just to partition the other two disks in
> the same way as the first?

sfdisk -d /dev/sda | sfdisk /dev/sdb 

is safe.

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