ZFS installs on HD with 4k physical blocks without any warning as on 512 block size device

Aled Morris aledm at qix.co.uk
Fri Aug 19 12:50:41 UTC 2011


On 19 August 2011 11:15, Tom Evans <tevans.uk at googlemail.com> 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.
>
...
> 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?
>
> 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.
>
>
At what point should we change the default in newfs/zfs to 4k?

I guess formatting the filesystem for 4k sectors on a 512b drive would still
work but it would be suboptimal.  What would the performance penalty be in
reality?

Aled


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