question on vinum

[Marko Raiha]

Hi,

On Wed, Oct 27, 2004 at 09:10:39AM -0600, secmgr wrote:
> The reason is empirically derived.  When I created a 7 disk raid 5 set 
> using "len 0" or all the space available, the raid set would be corrupt 
> after initializing.  Every time.  When I reserved back  that extra 
> space, no corruption.
> (freebsd 4.10-p3)  There was a thread on this a few days ago.

Thanks about pointing to this another thread. I read the thread and one
thing is still a bit unclear. Do you mean by leaving 64 blocks unused to
leave it unused at the beginning of disk before vinum partition (when
doing partition to vinum by disklabeling freebsd slice) like this:

# /dev/aacd2s1:
8 partitions:
#        size   offset    fstype   [fsize bsize bps/cpg]
  c: 143347932        0    unused        0     0 
  h: 143347868       64    vinum

or somewhere in subdisk as you said? I guess that inadvertently not
right terms were used ("subdisk" instead of "disk"), because terminology
with vinum is a bit complicated.

All documentations I have found says that only 16 block should be left
unused at the beginning of the disk like this:

# /dev/aacd2s1:
8 partitions:
#        size   offset    fstype   [fsize bsize bps/cpg]
  c: 143347932        0    unused        0     0
  h: 143347916       16    vinum

Regards,
-- 
Marko Räihä