Subject: Re: ccd, disklabel
To: None <port-i386@netbsd.org>
From: Jens A Nilsson <jnilsson@ludd.luth.se>
List: port-i386
Date: 11/02/1998 21:08:36
Tom T. Thai <tomthai@future.net>,wrote on Nov 02, 1998 at 13:09 -0600: 
> On Mon, 2 Nov 1998, Jens A Nilsson wrote:
> > The problem is that you need an offset for the partitions you ccd.
> > Look at ccd(4), it's described in the beginning of the manpage.
> 
> man ccd:
> ...
>      Note that the `raw' partitions of the disks should not be combined.
>      Each component partition should be offset at least one cylinder from
>      the beginning of the component disk.  This avoids potential conflicts
>      between the component disk's disklabel and the ccd's disklabel.  The
>      kernel will only allow component partitions of type FS_BSDFFS.
> ...
> 
> given that all my disks are laid out the same per disklabel below for each
> disk:
> ...
> #        size   offset    fstype   [fsize bsize   cpg]
> a:   224700        0      4.2BSD     1024  8192    16   # (Cyl.    0-99)
> b:   224700   224700        swap                        # (Cyl.  100-199)
> c:  8340864        0      unused        0     0         # (Cyl.    0-3711)
> d:  8340864        0      unused        0     0         # (Cyl.    0-3711)
> e:  7891464   449400      4.2BSD     1024  8192    16   # (Cyl.  200-3711)
> 
> so if I want to ccd each partition of each disk sdXa into ccd1, then I
> have to offset partition a from the original disklabel?  i.e. partition a
> above (for each sdx) should be:
> 
> a:   224700        1      4.2BSD     1024  8192    16   # (Cyl.    0-99)
>                   --- <-- changed from 0 to 1
Change that to what's written after "sectors/cylinder:"

> 
> what about partition e for each disk?  should that be offset by one too?
> i have ccd0 using all the partitions sdXe right now with out that offset.
No that's not necessary since there is no risk for conflict there.

> 
> oh a side note, where is the disklabel for a ccd really written?
Since you got the disklabel from sd0 I suppose that it's put at
the begining of the first partition you ccd.

-- 
mvh Jens