On Sat, 2005-06-11 at 14:42 -0400, Mike Jakubik wrote:> Can someone explain tome the difference between a RAID1 setup done via
> atacontrol and gmirror? I have a VIA 6420 SATA150 controller, which also
> has raid, but is not supported by -stable.
Here are the main differences, as I see them:
atacontrol RAID:
- Only for ATA;
- Compatible with quite a few ATA RAID card BIOS metadata formats, hence
you can create the RAID using the RAID controller's BIOS menu;
- Supports only two-way mirroring (IIRC);
- Supports spares.
gmirror:
- Works with any GEOM provider (ATA, SCSI, ggate, etc.);
- Uses the last sector of each RAID component to store its own metadata;
- Supports N-way mirroring;
- Does not support spares (though gmirror activate/deactivate can be
used to associate a component with a mirror somewhat akin to having a
spare).
I found array rebuilding to be troublesome on atacontrol RAID---so much
so I abandoned it and used vinum and then gmirror instead for my RAID 1.
(I have a bootable geom_mirror setup, now.) Mind you, that was in the
pre-ATA mk.III days, and I hear the RAID support underwent a big revamp
in the mk.III rewrite.
Cheers,
Paul.
--
e-mail: paul@gromit.dlib.vt.edu
"Without music to decorate it, time is just a bunch of boring production
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