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Date:      Mon, 26 Apr 2010 21:10:12 +0200
From:      Pawel Jakub Dawidek <pjd@FreeBSD.org>
To:        "M. Warner Losh" <imp@bsdimp.com>
Cc:        mav@FreeBSD.org, freebsd-current@FreeBSD.org, freebsd-geom@FreeBSD.org
Subject:   Re: Switchover to CAM ATA?
Message-ID:  <20100426191012.GA1711@garage.freebsd.pl>
In-Reply-To: <20100426.121946.506212773266921087.imp@bsdimp.com>
References:  <4BD06BD9.6030401@FreeBSD.org> <20100426.103327.319083499807534535.imp@bsdimp.com> <20100426181209.GB3012@garage.freebsd.pl> <20100426.121946.506212773266921087.imp@bsdimp.com>

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On Mon, Apr 26, 2010 at 12:19:46PM -0600, M. Warner Losh wrote:
> In message: <20100426181209.GB3012@garage.freebsd.pl>
>             Pawel Jakub Dawidek <pjd@FreeBSD.org> writes:
> : On Mon, Apr 26, 2010 at 10:33:27AM -0600, M. Warner Losh wrote:
> : > I've read most of this thread.  I think this is cool technology.
> : > However, before we move forward with this, we need to have a plan for
> : > the various issues that have come up.  The plan needs to be specific,
> : > have owners for key items, warnings about ownerless =3D=3D obsoleted,=
 and
> : > target dates.
> : >=20
> : > I think this is one of the cases where we should record the plan of
> : > record on a wiki.  It worked well for other times we've had big,
> : > disruptive changes.
> : >=20
> : > My opinion for the path forward:
> : > (1) Send a big heads up about the future of ataraid(5).  It will be
> : >     shot in the head soon, to be replaced be a bunch of geom classes
> : >     for each different container format.  At least that seems to be
> : >     the rough consensus I've seen so far.  We need worker bees to do
> : >     many of these classes, although much can be mined from the ataraid
> : >     code today.
> :=20
> : This shouldn't be a bunch of GEOM classes. This should one class which
> : recognize multiple formats, just like the LABEL class.
> : I don't think it is feasible to reuse gmirror for that, it wasn't
> : designed in something like this in mind.
>=20
> OK.  Maybe I got the consensus wrong...  My key point is that we need
> a plan moving forward, we need to identify what's actively being
> worked on vs "somebody else[tm] should do tihs" and when it needs to
> be done "or else".

You most likely got it right, I'm just saying creating separate GEOM
class for each metadata format is wrong direction. :)

> : > (5) Issues with glabel and ataraid(5) need an owner, and need to be
> : >     resolved, since the device names here are likely to change.
> :=20
> : What are the issues?
>=20
> ataraid doesn't remove the underlying ad* devices, so glabel often
> picks those up instead of the ataraid device, and you only get 1
> disk's worth of raid device...  So no mirroring or only 1/2 a striped
> volume.

It not only leave ad* devices, it doesn't even open them properly using
GEOM. It's internal ATA hack, which is PITA.

--=20
Pawel Jakub Dawidek                       http://www.wheelsystems.com
pjd@FreeBSD.org                           http://www.FreeBSD.org
FreeBSD committer                         Am I Evil? Yes, I Am!

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