question on vinum

[secmgr]

Marko Raiha wrote:

>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,
>  
>
That probably would have worked too.  My mistake was to clone the c 
partition entry, call it h, label it vinum, and use that