ICH5R, ICH7R or Promise PDC20378 RAID?

Ted Mittelstaedt tedm at toybox.placo.com
Fri Jun 23 14:56:31 UTC 2006

----- Original Message ----- 
From: "Philippe Lang" <philippe.lang at attiksystem.ch>
To: "Ted Mittelstaedt" <tedm at toybox.placo.com>; "Doug Poland"
<doug at polands.org>
Cc: "freebsd-questions" <freebsd-questions at freebsd.org>
Sent: Friday, June 23, 2006 1:46 AM
Subject: RE: ICH5R, ICH7R or Promise PDC20378 RAID?

> Ted Mittelstaedt wrote:
> >> Hi,
> >>
> >> I'm sure there are solutions to make things work, but personnaly, I
> >> don't feel confortable with a RAID system that acts that way, and
> >> that is supposed to make the whole system more robust and
> >> problem-free.
> >
> > Your missing the point.
> >
> > If a disk crashes it wipes the metafile off the disk.
> >
> > If you want to simulate a disk crash, issue a raid detach command
> > first, then pull the disk.
> >
> > The ata raid in the ata driver isn't written to handle the
> > condition of
> > a disk being pulled that has nothing wrong with it then reinserted.
> > It is written to handle the condition of a disk crashing, then being
> > pulled, then a new one replaced.
> >
> >> I used to play with hardware SCSI RAID controllers, and was never
> >> able to trash the system.
> >
> > I have SCSI raid controllers too that I can do that with.  But keep in
> > mind that these controllers firmware is written to if a disk
> > is pulled then
> > replaced, it immediately assumes that the disk is toast, and
> > rebuilds it
> > from scratch.
> Hi,
> I'm not an expert in RAID Ted, and I don't want to be. Simply, in
situations where a disk crashes, and the server is not redundant anymore, I
prefer having a controller that I can rely on, both eyes closed. I have just
installed the 3WARE controller this morning, and did the exact same
operations I did with the ICH5/7R and onboard Promise controller of my ASUS
boards. It's simply not comparable at all, and for a really affordable
price. The server did not crash, and is by the way rebuilding the RAID at
the moment... Despite all my efforts, I was not able to trash it.
> A 3WARE controller is really worth the investment, really.

Ah, you must of missed the thread where I recommended the 3ware controller
to someone complaining that there wasn't any hardware support for FreeBSD.
I happen to have a couple of the 3ware controllers myself.

The 3ware controller works but so does the integrated RAID in the ata
driver - if you know how to handle it, and you have the right hardware.  And
granted, the man page does not do a good job of documenting how to recover
from a crashed disk.  However, not everyone thinks $200 USD is a "really
affordable price" and if all you want to do is mirroring then the integrated
RAID is fine.  Keep in mind that in a 1U server, you don't have room for
more than 2 disks anyway.

The 3ware controller's main strength over the integrated RAID is that it
has additional features, like RAID-5, offline rebuild, etc.


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