Using GTP and glabel for ZFS arrays

[Adam Vande More]

On Wed, Jul 21, 2010 at 10:34 PM, Adam Vande More <amvandemore at gmail.com>wrote:

>
>
> 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.
>
>
Also if you have an applicable SATA controller, running the ahci module with
give you more speed.  Only change one thing a time though.  Virtualbox makes
a great testbed for this, you don't need to allocate the VM a lot of RAM
just make sure it boots and such.

-- 
Adam Vande More