Using GTP and glabel for ZFS arrays

[Adam Vande More]

On Wed, Jul 21, 2010 at 10:05 PM, Dan Langille <dan at langille.org> wrote:

> Why '-b 34'?  Randi pointed me to
> http://en.wikipedia.org/wiki/GUID_Partition_Table where it explains what
> the first 33 LBA are used for.  It's not for us to use here.
>
> Where SOMEVALUE is the number of blocks to use.  I plan not to use all the
> available blocks but leave a few hundred MB free at the end. That'll allow
> for the variance in HDD size.
>
> Any suggestions/comments?  Is there any advantage to using the -l option on
> 'gpart add' instead of the glabel above?
>

You'll want to make sure your partitions are aligned, discussion here(says
4k drives, but info pertinent to all):

http://lists.freebsd.org/pipermail/freebsd-hackers/2010-March/031154.html

My understanding is that you weren't booting from zfs, just using it as an
data file system.  In that case, you'd want to use "gpart add -b 512 ..."
 or some other multiple of 16.  Even 1024 would be a good safe number.  Also
GPT creates partitions not slices.  Your resulting partitions with be
labeled something like ad0p1, ad0p2, etc.



-- 
Adam Vande More