[CentOS] building software raid.

[Fred Smith]

On Sat, Nov 02, 2013 at 03:26:47PM +0100, Johan Vermeulen wrote:
> 
> Op 01-11-13 17:41, Johan Vermeulen schreef:
> > Op 30-10-13 17:38, John Doe schreef:
> >> From: Johan Vermeulen <jvermeulen at cawdekempen.be>

<big snippage>

> 
> /Dear All,
> 
> I would like to renew my request for help with this wiki:
> 
> http://wiki.centos.org/HowTos/Install_On_Partitionable_RAID1
> 
> Still stuck on EM : dracut warning: No root device "block:/dev/md_dop3" 
> found.
> I think this is a bit of a pain to troubleshoot, because
> 
> * to change anything, I have to chroot to /mnt/sysimage every time.
> * googling this, I see a a threat marked solved here :
> https://www.centos.org/modules/newbb/print.php?form=1&topic_id=43676&forum=55&order=ASC&start=0
> 
> but I can't access it.
> 
> So far I tried this :
> 
> *  http://lists.centos.org/pipermail/centos/2013-March/133176.html
> 
> so i ran  dracut --mdadmconf initramfs.......
> 
> but that did change anything
> 
> * 
> http://grokbase.com/t/centos/centos/133qevz1d8/cant-find-root-device-with-lvm-root-after-moving-drive-on-centos-6-3
> also mentions an almost empty /dev/mapper,
> so I am now trying to make a correct symlink in /dev/mapper in order to 
> be able to boot the system.
> 
> So far I haven't found the right one.
> 
> Can anyone shed some light on this?
> 
> Many thanks.
> 
> J./
> //

There used to be another RAID HOWTO on the Centos Wiki, I have a printout
of it here, somewhere,... I used it when I built a new box a few years
ago on Centos-5 and it worked fine. where "fine" means when one of the
drives gave some sort of problem it got ejected from the RAID array and
the system continued to work properly. And replacing it allowd me to
rebuild the array and proceed.

When I did a bare-metal installation of Centos-6 at the beginning of this
year I went looking for the newest version of it, and it no longer seemed
to be available at the URL it says it came from. But I used it anyway even
though it wasn't exactly perfect for C6, it was close enough that it wasn't
difficult to figure out what should be done, and I've got a nice Raid-1
system running here now.

I'd give you the URL it claimed to be from if I could find the printout,
and if it turns up soon I'll come reply to this mail and give it if the
URL is in fact working.

-- 
---- Fred Smith -- fredex at fcshome.stoneham.ma.us -----------------------------
                      The eyes of the Lord are everywhere, 
                    keeping watch on the wicked and the good.
----------------------------- Proverbs 15:3 (niv) -----------------------------