3TB drives on ZFS and booting

[krad]

On 24 July 2011 22:52, Gary Corcoran <gcorcoran at rcn.com> wrote:

> I have seen conflicting information on the internet about this, and so
> I would like a direct answer from someone who knows for sure.  Does
> FreeBSD's
> ZFS work with 3TB drives, and is it possible to do a ZFS-only (i.e. boot
> from
> ZFS) installation with 3TB drives on FreeBSD?  I presume that since ZFS was
> designed
> to handle huge filesystems, it would have no problem with 3TB drives, but I
> guess
> the real question is the ZFS boot code - can it currently handle >2TB
> drives?
> Bottom line: would I be able to successfully build (and of course boot) a
> FreeBSD
> ZFS-only system using only 3TB drives?
>
> Thanks,
> Gary
>
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The main issue with 3tb drives will be the 4k sector size. This applies to
most of the 2tb drives as well. Make sure you use GPT layout and align it.
IE make sure each gpt partiion start sector is / by 8 and its size is. Here
is mine for an example

$ gpart show ada0
=>        34  3907029101  ada0  GPT  (1.8T)
          34           6        - free -  (3.0k)
          40         128     1  freebsd-boot  (64k)
         168     6291456     2  freebsd-swap  (3.0G)
     6291624  3900213229     3  freebsd-zfs  (1.8T)

also make sure you use gpt boot blocks that can cope with 4k aligned drives.
Use the ones from current or these binary ones
http://people.freebsd.org/~pjd/zfsboot/