On Thu, Nov 17, 2005 at 04:47:03PM +0100, Markus Wernig wrote:
> Hi misc
>
> Is anybody aware of a document that describes how to ccd all slices
> (including /) after installation?
> I've installed 3.8 generic using just one of two identical disks. Now I
> need to mirror that disk onto the other one. I copied the disklabel from
> the active disk over. I can of course create ccd's for each slice, but
> this means newfs and data loss, and won't work because I can't umount
> the root.
> Now I assume that my approach was intrinsically bound to fail or just
> dumb wrong. I'm sorry if this is covered somewhere public - I found
> references to a FAQ on MARC, but was just unable to find my question
> covered in the related documentation.
> One thing I came up with was to boot from install media and do it from
> the shell there, then newfs and reinstall on the ccd devices. But I'm
> really not quite sure.
>
> The goal is to bring the box back online as fast as possible after a
> disk crash and replacement, and to be then able to rebuild the raidset
> online (dd is fine).
>
> thx /markus
Well, it's not ccd, but there are a couple of documents around that
describe how to put root on a RAID-1. This requires a custom kernel, but
works very well - for me at least.
And if the point is disaster recovery, a RAID-1 is as good as ccd if you
keep a spare custom kernel somewhere.
I seem to recall that the kernel will not autoconfigure ccd. That means
you can't put / on it, without monkeying around at least. However, you
could put / on a RAID-1, and then use ccd for the rest (if truly
paranoid, turn most of /etc, /opt, /dev and so on into symlinks to a ccd
mount...)
Joachim
