Date: Sun, 25 May 2014 12:46:45 -0400 From: Allan Jude <allanjude@freebsd.org> To: freebsd-sysinstall@freebsd.org Subject: Re: bin/164281: bsdinstall(8): please allow sysinstall as installer option Message-ID: <53821E75.10000@freebsd.org> In-Reply-To: <53821DC6.60701@freebsd.org> References: <201404151630.s3FGU0Zg026166@freefall.freebsd.org> <CAM9wqY8Bn9yQvMbpMdg1wcVhx5AGgK6rP1tkh9qccDhWZaU9Kw@mail.gmail.com> <012501cf5f1f$c5e7c740$51b755c0$@FreeBSD.org> <5358223B.1090408@gmail.com> <535827AC.3040503@allanjude.com> <53582CC4.2080808@freebsd.org> <53583D5C.5020506@pix.net> <53583DB8.1080905@freebsd.org> <20140423230210.GA20429@pix.net> <538219DA.3040702@freebsd.org> <53821B1F.8000509@freebsd.org> <53821DC6.60701@freebsd.org>
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This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --9D2pMIsBVITkaNOrH6OMq4qPO73nxaUuV Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 2014-05-25 12:43, Nathan Whitehorn wrote: > On 05/25/14 09:32, Allan Jude wrote: >> On 2014-05-25 12:27, Nathan Whitehorn wrote: >>> I'm (finally) integrating these patches now. Could you remind me what= >>> the point of the gnop is? I'm not sure I get it. >>> -Nathan >> The 'gnop -S 4096 <device>' makes a virtual device that has a sector >> size of 4096 bytes. This causes ZFS to set ashift=3D12 even for device= s >> that mis-advertise (lie about) their sector size. There is no real har= m >> in using 4k sectors on a 512b sector device, but using 512b sectors on= a >> 4k device will cause write amplification (read-modify-write) since the= >> device will have to deal with it as a partial block update. >=20 > I think our ATA code mostly has this under control at this point. >=20 >> Additionally, the sector size can only be set at pool creation time, >> even if you have have 512b sector devices, you'll want to create your >> pool as 4k, so that in the future when you add additional devices, or >> replace failed devices, the 4k sector devices will be supported. ZFS >> complains loudly when you try to add mis-matched sector size devices t= o >> a pool. >> >> >=20 > This is a good reason, even if the circumstances behind it are stupid. > Is there really no way to handle this besides gnop? Can't we just fix Z= FS? > -Nathan > _______________________________________________ > freebsd-sysinstall@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-sysinstall > To unsubscribe, send any mail to > "freebsd-sysinstall-unsubscribe@freebsd.org" Linux added an explicit option to the zpool, so you can just do: zpool create -o ashift=3D12 mypool mirror disk1 disk2 There was some discussion about this in the OpenZFS group, but it was usually cited as a reason why there was a need to for OpenZFS, to keep the Linux version from diverging and adding a bunch of non-standard optio= ns. I am not sure what the best option is. The gnop is only required while the pool is being created, it doesn't need to be re-created in order to import the pool etc, it is just to trick ZFS the first time. --=20 Allan Jude --9D2pMIsBVITkaNOrH6OMq4qPO73nxaUuV Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (MingW32) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBAgAGBQJTgh54AAoJEJrBFpNRJZKfp/wQAI8bzYdlC4z9yoyWaNWbyLB9 7zlLXUoy46ax7IJZjO3HV9dUX+hQHI8wyVoEuWav+508KhVYGH0Yrj5SxVOO9CFL GxOBuZRU5UAkLeVMuot82OJdab9eb7L+dASmvwF2V0J0tdbgw+RgpFWTZhm+Gl7s xylzZOAfSs1/lKdMOtbs/u2XYejzrrnWtZzDgZ73sSolGG15HyLbFpcoCfUG9MN4 hJl4OOD1J9dI5DFkS/OTrgRilB6RcAODC8lJwfBykEqBSAk/bzX71kGbrIM8y6YS QJ79cQPn6i+fw4k+Mu99V9tlxigGWFxR5pr3OLHQ+0AKNyqOi/DhkBcrp7Pqtxc4 mfkKOMaWi7Inz0TNh4UuVmzl3Qwi0zrjgyY+4k/LlqUk5afQLbtbOkfFFrZkeql/ UzEyew+/HRGBgBw8CaZz7LZbeEnE3RXtoXxQ5fNUbPtzAxJ44RtX6HlkklPov2nS xmiiLoLlsK01fLtg6xeRJ/yVeMDYOToN7K2dmlVbIaQBRxN86ldTC4Qr2m9JCHz6 HRY+ee6LxZB2C87fas062R4KyZK+sZBOknf3ZrbtC4itoE08uewXerHlJMuHmQ4y Dc+pQWyKe+t7peECY1zXfXVfjf6PlX56YlSrbwx0d/8MJy/IuPbPClPGzRVswifz 99ExiAQwQoJCCxFvb0uS =74Pn -----END PGP SIGNATURE----- --9D2pMIsBVITkaNOrH6OMq4qPO73nxaUuV--
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