ZFS - whole disk or partition or BSD slice?

Volodymyr Kostyrko c.kworr at gmail.com
Mon Jan 28 09:38:34 UTC 2013

28.01.2013 08:05, Michael Sierchio:
> On Sun, Jan 27, 2013 at 5:36 PM, Shane Ambler <FreeBSD at shaneware.biz> wrote:
>> I recall reading that using partitions for zfs on FreeBSD was as good as
>> full disks.
> No, it isn't - ZFS can fully utilize disk caches when presented with
> whole devices. There are possible reasons to create partitions - one
> being that if an unfriendly OS sees the device, it won't try to
> initialize it if it sees a partition map.  Another is using a cheap
> RAID controller that can't be fully disabled - in which case you
> generally need to create a partition that doesn't include the last few
> sectors of the disk, where such controllers keep magic data.

That's wrong for long ago. This problem was solaris specific. Current 
ZFS code sees no difference between disks and partitions. One should 
think twice when putting two vdevs on one physical disk though.

Sphinx of black quartz, judge my vow.

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