Re: [PLUG] Survey: Linux RAID mirror sync time

[Rich Freeman <r-plug@thefreemanclan.net>]

On Mon, Mar 4, 2013 at 8:55 PM, Eric at Lucii.org <eric@lucii.org> wrote:
> Short answer:  I don't think so.
>
> Longer answer:  You have to use fdisk to change the partition type to "Linux RAID Autodetect".
> I believe that process will likely wreck the data already on the drive.
>
> Caveat:  I have not tried this.
>
> I will be trying something similar on Wednesday with a system that was supposed to be set
> up with RAID mirroring but was not.

I forgot setting the partition types - as you partition the new drive
and repartition the old one in the procedure I gave be sure to set the
type accordingly.

However, you cannot just change the partition type on a non-RAID
partition to RAID and expect it to work.  It might still mount as
ext3/etc - I suspect it won't hose your drive, but I've never tried
this.

You need to set up a RAID on the NEW drive, and move your data over to
it, then extend that RAID back over your old drive.  Moving the data
over is considerably easier with LVM, but that's still the basic
approach.  /boot won't be on LVM so it needs special handling either
way (again, unless GRUB2 now supports booting off of LVM+RAID, in
which case you can just move everything and re-install/configure
GRUB).

I've migrated everything before, but it is entirely possible I missed
a step in my email.  You should definitely be comfortable with the
concepts before attempting this.  I'd be pretty confident that if
something went wrong that I could figure out what I missed and fix it.
 If you aren't feeling the same then you probably should do more
research.

Rich
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