[CentOS] converting system to raid1

[Les Mikesell]

Dave wrote:
> Hello,
>    I've got a single-drive CentOS5 system with two partitions on it, a 
> 101 mb boot, and the rest of the disk as an lvm volume, two partitions 
> in it, / and swap. I've got another disk, same size, and i'd like to add 
> it in as a primary slave drive and convert this system to raid1 for 
> redundancy. I do not want to reinstall this box, which is what the docs 
> i've read say it's easiest to do. Some elude to a procedure, hard yes, 
> time consuming with copying probably, that can do it. Has anyone done this?
> Thanks.
> Dave.

I've seen those procedures and it seemed crazy enough that I didn't 
bother saving the link... I'd probably tackle it by adding the 2nd drive 
and making similar-sized raid1 partitions on it with a member specified 
as 'missing', then make filesystems, LVM, etc., copy your existing data 
over, install grub, adjust it's copy of /etc/fstab, and boot the new 
disk.  Once you are sure the new setup is good, use mdadm to add the 
partitions of the original drive into the raid1.  The advantage of this 
approach is that unless you do something like copy the wrong direction 
you can always go back to the old version until the new one has been 
proven to work.

-- 
   Les Mikesell
    lesmikesell at gmail.com