ZFS installs on HD with 4k physical blocks without any warning
as on 512 block size device
Pieter de Goeje
pdegoeje at service2media.com
Fri Aug 19 12:17:55 UTC 2011
On Friday, August 19, 2011 12:15:30 PM Tom Evans wrote:
> On Thu, Aug 18, 2011 at 6:50 PM, Yuri <yuri at rawbw.com> wrote:
> > Some latest hard drives have logical sectors of 512 byte when they
> > actually have 4k physical sectors. Here is the document describing what
> > to do in such case:
> > http://ivoras.net/blog/tree/2011-01-01.freebsd-on-4k-sector-drives.html .
> > For UFS: newfs -U -f 4096 /dev/da0
> > For ZFS: gnop create -S 4096 /dev/da0 && zpool create data /dev/da0.nop
> > I am sure most people just install such hard drive without doing this and
> > potentially get suboptimal performance since they aren't aware about
> > this. Shouldn't UFS and ZFS drivers be able to either read the right
> > sector size from the underlying device or at least issue a warning?
> > Yuri
> The device never reports the actual sector size, so unless FreeBSD
> keeps a database of 4k sector hard drives that report as 512 byte
> sector hard drives, there is nothing that can be done.
In -current at least there is a quirk table for these drives - the stripe size
is set to 4K. Other tools use this size to align stuff on. Also, the default
fragment size of UFS was increased to 4K.
More information about the freebsd-hackers