geom_mirror implementation

[Lukas Ertl]

On Sun, 9 Nov 2003, David Schultz wrote:

> Yeah, RAID support in FreeBSD is in a rather sorry state right
> now.  ccd(4) doesn't work with ATAng on my machine without causing
> panics and data corruption, raidframe is broken in -CURRENT, and
> vinum tends to lag behind changes and break.  But that doesn't
> mean that the right solution is to add a *fourth* incompatible
> RAID implementation.

Yes, this is a good point.  The advantage I see in geom_mirror is that it
fits into the GEOM framework and doesn't take a lot to set up.

> If there's a good reason ccd(4) is harder to fix than geom_mirror, then
> you might want to talk to phk about rewriting geom_ccd based on
> geom_mirror.  I believe scottl and phk have plans to fix raidframe,
> though, which would address a lot of the present limitations.

I haven't used ccd or raidframe before, and vinum is still a lot of
'voodoo'. I just wanted to play around and do something useful;
furthermore I learned a real lot about GEOM internals.

regards,
le

-- 
Lukas Ertl                             eMail: l.ertl at univie.ac.at
UNIX Systemadministrator               Tel.:  (+43 1) 4277-14073
Vienna University Computer Center      Fax.:  (+43 1) 4277-9140
University of Vienna                   http://mailbox.univie.ac.at/~le/