Date: Sun, 28 Feb 2010 02:09:06 +0100 From: Pawel Jakub Dawidek <pjd@FreeBSD.org> To: Dimitry Andric <dimitry@andric.com> Cc: freebsd-fs@freebsd.org Subject: Re: zfs on 4k sector disks Message-ID: <20100228010906.GD2586@garage.freebsd.pl> In-Reply-To: <4B7FD4D2.7040802@andric.com> References: <e7531071831ef4c088902a8b5fe94dab, 4B7FAF99.10308@debank.tv> <4B7FD4D2.7040802@andric.com>
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--MPkR1dXiUZqK+927 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, Feb 20, 2010 at 01:25:54PM +0100, Dimitry Andric wrote: > On 2010-02-20 10:47, mailinglists wrote: > >This "Advanced Format" basically means the sectors size on disk is > >changed to 4k in stead of 512k. >=20 > Please note those disks still seem to expose 512B sectors to any OS; the > 4kiB sectors are only used internally. And there seems to be no jumper > to "fix" this behaviour... Unaligned writes can cause multiple > read-write-modify operations, which are most likely bad for performance. You can "fix" that with: # gnop create -S 4096 /dev/ad0 This command will create /dev/ad0.nop provider, which will expose 4kB sector (see diskinfo(8)). Unfortunately gnop won't survive reboot, as it doesn't use any metadata. --=20 Pawel Jakub Dawidek http://www.wheel.pl pjd@FreeBSD.org http://www.FreeBSD.org FreeBSD committer Am I Evil? Yes, I Am! --MPkR1dXiUZqK+927 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.14 (FreeBSD) iEYEARECAAYFAkuJwjEACgkQForvXbEpPzQ7SQCfbE40UkwzUdQtI6UwpcLKRxAE hjIAoJ+zRgrlQYIq23CUYy961nesw7+O =SN+L -----END PGP SIGNATURE----- --MPkR1dXiUZqK+927--
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