[arch-general] limited softraid support in AIF (WAS:Why Is My RAID Installing Failing?)

[Dieter Plaetinck]

On Thu, 14 Jan 2010 00:07:18 +0100
Alexander Duscheleit <jinks at archlinux.us> wrote:

> Would it be possible to just generate the relevant mdadm.conf during
> the configure stage without providing further additional support?
> People are used to run installation steps in sequence so this would
> eliminate on source of (apparently frustrating) user error.
> 
> A quick look at AIF's source suggest prefill_configs () as proper
> place. I'm not certain, how AIF identifies used block devices, but
> something like this would probably suffice:
> 
> if md[0-9] in $BLOCKDEVICES ->
>       mdadm --detail --scan >> ${var_TARGET_DIR}/etc/mdadm.conf


hmm. that seems simple enough. why not?
what do you mean with $BLOCKDEVICES ? all blockdevices in the system?
or blockdevices explicitly configured to be partionened by user? or
blockdevices explicitly configured to be used for formatting by user?

> > If the official installation guide states otherwise, we should fix
> > that. please point me to the mistake/file a ticket.
> > If community-maintained documentation is incorrect, fix it yourself.
> 
> The official istall guide specifically states that you are on your own
> with softraid. The raid/lvm/etc wiki article is a bit twisted in it's
> mix-and-match of methods, I shall have another look if I can squeeze
> the relevant information in there.

the better the support in AIF gets, the smaller such articles can
become.

> > Patches to support softraid are always welcome.  Things don't get
> > improved by merely hoping for it.
> > http://bugs.archlinux.org/task/14149
> 
> WONTFIX! This is already far too easy :)

Assuming the user does the heavy work (creating the MD volumes), what
are the other (little) tasks that AIF can implement to limit the amount
of manual work?

- modprobe raid{1,2,3,4,5,6} ?
- rewriting the mdadm.conf if needed (see above)
- for a root filesystem which needs raid, add raid to HOOKS in
  mkinitcpio.conf [where order is very important when combined with
  lvm/dm_crypt etc] ?

anything else i'm missing?

Dieter