Re: setting up raid5

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Mon, May 31, 2010 at 09:33:43PM +1000, Simon Burge wrote:
> Steven Bellovin wrote:
> 
> > I'm trying to set up a raid5 configuration across 3 disks.  It isn't =
> > working right...
> > 
> > I used this as raid1.conf:
> > 
> > START array
> > 1 3 0
> 
> You want
> 
>       START array
>       1 2 1
> 
> there - 1 row with 2 disks and 1 spare disk.  The example for a
> 4 disk RAID5 is "1 3 1".

I don't think so. The "spare disk" is a hot spare. If he doesn't want one,
the last number can be 0.

> 
> > START layout
> > 512 1 1 5
> 
> I'm not 100% sure, but I think you're limited to 128 sectors per
> stripe unit (64kB or MAXPHYS) here.  Maybe try the "32 1 1 5" as
> per the example first, and bump higher when the rest is working.

Yes, this is likely the problem. raidframe will schedule a transfer
larger than MAXPHYS, and the underlying driver will bail out.

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--