Subject: Re: RAIDframe initialization / overlapping dump-device
To: Greg Oster <oster@cs.usask.ca>
From: Petar Bogdanovic <list+2007@smokva.net>
List: netbsd-users
Date: 11/14/2007 16:31:00
On Wed, Nov 14, 2007 at 09:19:47AM -0600, Greg Oster wrote:
> Petar Bogdanovic writes:
> > Hi,
> > 
> > raidctl(8) says:
> > 
> > 	``-i (...) MUST be done for all RAID sets before the RAID device
> > 	     is labeled and before file systems are created on the RAID
> > 	     device.''
> > 
> > I usually don't question sentences which begin with a uppercase must but
> > since I forgot to initialize my raid0 before doing all the labels and
> > file-systems it makes me wonder why my system works, resp. why it could
> > fail without a prior initialization.
> 
> If the parity on the RAID set is not in sync and a component dies, 
> then data will likely be lost (and/or filesystems corrupted, panics, 
> etc.)  If you can live with that risk, then you are free to 
> initialize the parity when you please.  To be safe in the general 
> case, however, you will want to initialize the parity *before* using 
> the RAID set.  The "MUST" is there to encourage the initialization of 
> parity early on.  It is there especially for those folks who do not 
> know (or don't wish to know) the implications of not doing the parity 
> initialization before trusting data to the set...

Thanks, that's exactly what I wanted to know. :)


Petar