CentOS - Jan 2012 - doing a new install on top of existing software raid-1

Hi all!

One of these days I'm going to upgrade my centos 5.7 box (which is
currently configured with raid-1 on two drives) to 6.x.

i've been given to believe that I should be able to do a fresh install
on top of the existing raid setup, i.e., without having to re-create
the raid array, but just use the existing setup.

and somewhere in the last few days (in this list I think) someone posted
that Anaconda should detect the existing raid array and allow you to re-
use it for a new install.

so just as an experiment, I booted up the 6.2 DVD (not live) and took it
as far as where it sets up the partitioning. So, was I unduly surprised
when it DID NOT detect the existing raid? well, a little. more in the 
category of NOT ENTIRELY PLEASED, actually.

I'd appreciate it if someone who knows something about linux hardware
raid, and its intersection with Anaconda, could drop a few clues in my
direction.

thanks in advance!

-- 
---- Fred Smith -- fredex at fcshome.stoneham.ma.us
-----------------------------
  "And he will be called Wonderful Counselor, Mighty God, Everlasting
Father,
  Prince of Peace. Of the increase of his government there will be no end. He 
 will reign on David's throne and over his kingdom, establishing and
upholding
      it with justice and righteousness from that time on and forever."
------------------------------- Isaiah 9:7 (niv) ------------------------------

On Thu, Jan 19, 2012 at 3:30 PM, fred smith
<fredex at fcshome.stoneham.ma.us> wrote:
> Hi all!
>
> One of these days I'm going to upgrade my centos 5.7 box (which is
> currently configured with raid-1 on two drives) to 6.x.
>
> i've been given to believe that I should be able to do a fresh install
> on top of the existing raid setup, i.e., without having to re-create
> the raid array, but just use the existing setup.
>
> and somewhere in the last few days (in this list I think) someone posted
> that Anaconda should detect the existing raid array and allow you to re-
> use it for a new install.
>
> so just as an experiment, I booted up the 6.2 DVD (not live) and took it
> as far as where it sets up the partitioning. So, was I unduly surprised
> when it DID NOT detect the existing raid? well, a little. more in the
> category of NOT ENTIRELY PLEASED, actually.
>
> I'd appreciate it if someone who knows something about linux hardware
> raid, and its intersection with Anaconda, could drop a few clues in my
> direction.
I tried to boot a 5.x system with several raid1 sets with a 6.0 live
dvd and not only did it not detect/match up the mirrors, it renamed
and broke them so they no longer worked on 5.x.  I think there are
major differences in the way the kernel handles things.   I probably
won't try to access existing arrays again unless someone else reports
success, and even then I'll probably pull one of the drives of each
set until I'm convinced it is safe to sync them back.

-- 
  Les Mikesell
     lesmikesell at gmail.com

On 01/19/2012 10:30 PM, fred smith wrote:
> Hi all!
>
> One of these days I'm going to upgrade my centos 5.7 box (which is
> currently configured with raid-1 on two drives) to 6.x.
>
> i've been given to believe that I should be able to do a fresh install
> on top of the existing raid setup, i.e., without having to re-create
> the raid array, but just use the existing setup.
>
> and somewhere in the last few days (in this list I think) someone posted
> that Anaconda should detect the existing raid array and allow you to re-
> use it for a new install.
>
> so just as an experiment, I booted up the 6.2 DVD (not live) and took it
> as far as where it sets up the partitioning. So, was I unduly surprised
> when it DID NOT detect the existing raid? well, a little. more in the
> category of NOT ENTIRELY PLEASED, actually.
>
> I'd appreciate it if someone who knows something about linux hardware
> raid, and its intersection with Anaconda, could drop a few clues in my
> direction.
>
> thanks in advance!
>
Are you sure LiveDVD has mdadm service installed and running? LiveCD 5.3 
was missing it, I have not looked at 6.x yet.

-- 

Ljubomir Ljubojevic
(Love is in the Air)
PL Computers
Serbia, Europe

Google is the Mother, Google is the Father, and traceroute is your
trusty Spiderman...
StarOS, Mikrotik and CentOS/RHEL/Linux consultant

On 01/19/2012 01:30 PM, fred smith wrote:
> and somewhere in the last few days (in this list I think) someone posted
> that Anaconda should detect the existing raid array and allow you to re-
> use it for a new install.
>
> so just as an experiment, I booted up the 6.2 DVD (not live) and took it
> as far as where it sets up the partitioning. So, was I unduly surprised
> when it DID NOT detect the existing raid? well, a little. more in the
> category of NOT ENTIRELY PLEASED, actually.
I'm probably the person that you're referring to.  Anaconda has to be 
able to detect existing RAID sets in order to perform upgrades.

In order for Anaconda to present you with the existing sets, you must 
select an upgrade (in which case you won't see any partitioning stage) 
or you must use the graphical installer and select "Create custom 
layout".  The text mode installer can no longer do this.