ZFS - whole disk or partition or BSD slice?

Volodymyr Kostyrko c.kworr at gmail.com
Mon Jan 28 09:36:45 UTC 2013

28.01.2013 03:36, Shane Ambler:
> On 28/01/2013 10:27, james wrote:
>> I have a 9.1 system with some SATA disks in RAIDZ, upgraded from 9.0.
>> The disks are all the same type, and I formatted them for FreeBSD and
>> put ZFS in a slice covering most of them.
>> I have seen suggestions for OpenIndiana etc that it is better to let ZFS
>> have the whole raw disk and that this can control the way it manages the
>> disk writeback mode.
>> Does this apply to FreeBSD and ZFS too?
>> Presumably the disks are currently FreeBSD-specific.  If I used raw
>> disks instead of slices, could I read them from a Solaris system too?
> I recall reading that using partitions for zfs on FreeBSD was as good as
> full disks. For a boot zpool we need to at least have a partition for
> the boot-code and one for zfs preventing the use of a full disk.

No, ZFS support booting from dedicated disks. There's a zfsboot file 
that should be written upon disk first sector and ZFS reservation space 
to make it bootable.

The bad sides are:

1. Difficulties with boot code upgrading.
2. No swap.

Sphinx of black quartz, judge my vow.

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