Re: Setting up raid correctly

[Martin Husemann <martin%duskware.de@localhost>]

On Sun, Feb 24, 2013 at 11:53:52PM +0000, Philip Mueller wrote:
> A few time ago I used FreeBSD with gmirror and to mount destroyed raid 
> storages in other OS was no problem, cause these raid storages were 
> handled as normal storages.

I can't parse that (and have no idea how FreeBSD handles this). I assume
you mean things similar to what some BIOSes call "raid support", which
would for example make on one of my machiens ld0 attach as "nvraid" and
phyiscally being identical to wd1 and wd2.

This, however, is not how raidframe works. It is not restricted to raid 1, so
there is no natural representations for arbitrary components.

In case of lossage, you still just access it as, e.g., raid0.

You can still access the components, while the raid is not configured, via
their original device name, but you would not be able to mount or fsck them -
unless you clearly know what you are doing [and have a good reason to do so,
which I can't see right now].

As stated above, on NetBSD you would just use the configured raid, and it will
work with some components missing - and do all the magic for you.

However, if you would realy need to, on NetBSD you could create a "run time
only" wedge, by looking at the gpt output, and then using dkctl to remove
the raid wedge (this does not change the gpt), and adding a 64 blocks smaller
one. This is a hack at extended expert level, and certainly not recommended
procedure.

Besides, I would not trust $other_os to be compatible enough at the filesystem
level, and in case of emergency just boot a setup/rescue CD and safe a
backup via NFS or whatever.

Martin