From owner-freebsd-current@freebsd.org Tue Dec 26 17:22:18 2017 Return-Path: Delivered-To: freebsd-current@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id D3E72EA3C75 for ; Tue, 26 Dec 2017 17:22:18 +0000 (UTC) (envelope-from ohartmann@walstatt.org) Received: from mout.gmx.net (mout.gmx.net [212.227.15.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "mout.gmx.net", Issuer "TeleSec ServerPass DE-2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4D5D57F4F1; Tue, 26 Dec 2017 17:22:18 +0000 (UTC) (envelope-from ohartmann@walstatt.org) Received: from thor.intern.walstatt.dynvpn.de ([78.55.225.232]) by mail.gmx.com (mrgmx001 [212.227.17.190]) with ESMTPSA (Nemesis) id 0MRXzM-1eNOTJ2p2m-00Sbhw; Tue, 26 Dec 2017 18:09:29 +0100 Date: Tue, 26 Dec 2017 18:09:01 +0100 From: "O. Hartmann" To: Allan Jude Cc: freebsd-current@freebsd.org Subject: Re: ZFS: alignment/boundary for partition type freebsd-zfs Message-ID: <20171226180928.21654d9d@thor.intern.walstatt.dynvpn.de> In-Reply-To: References: <20171226172521.611a89b0@thor.intern.walstatt.dynvpn.de> Organization: WALSTATT User-Agent: OutScare 3.1415926 X-Operating-System: ImNotAnOperatingSystem 3.141592527 MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; boundary="Sig_/Cvz1M0mb_N7h_yf_B8_YDGc"; protocol="application/pgp-signature" X-Provags-ID: V03:K0:2p0KzLIxfYyOsXdPIuCc/iSdmjKQVPz9ZpuqSijda5NA33KZK6P tW8RmEf2TWtuVbdDd/Z2qYJ2Tql6/TUFmIFtyH/CSx9hdq3Lk9p10fSLuO0bUt22n7tE42C lOzdPQO4bMXT7MK9hFe0CAwkTtXkTicQb/vyP9opsd4XAEKHEdBad+NwrXiaL8f8OMYBJd1 fCG7z9sJvHK2tFUhKZj+Q== X-UI-Out-Filterresults: notjunk:1;V01:K0:YhaFB/9UOYM=:zIQzOGpxzoTqNNsksYPCAV 037L9+6ZwQkOffCuWb92mFRxQp+jN/c1JnxL2L/PsXbFt4p0Q6XGcPv6M0lCONC9fK2HixQt1 e8D66T/68AVTAd5uMqvDEA52aDz441cJX4Y5rx+oAy0btV8rjB/EcFgJIBGzukLpBeQ7kocgn ZejnbvizLMvVNX+Mzan8/DIxfnRTGW4TIg2w6m3YRvLhvuXKolYZ2LH9rfP5N699eG+HRaIAQ MnOcEALgWoASPbBmfgn4Mk+lU7PqRuUGoTKpo+TQbIOpl1U9TqDP/CN77Fs9aIK4PjT16LfFo rKj7qThLLRXB8jjRi+QftSSnCkvGNaHcvD+ROyq6iPnyV3K+MW4iRz2+CxAPo3k4uxxpfL4Ea in2YrsEoQ7P6jlCbFjHNnNxGcTS+Ihafgm886K2S1LMN0UyTOm7YpmpuNX+uhZfa+UhdU7zT4 cOdQ5tf1He3CqUkoDiKECu/O3AMN0FGRBIjTVJHYUbVxraehXSwNCih9ugY7zWRdQvEJIn6vz M/tgnDxI7iljZt+o5X4TkRVNECVhrSzkyLmESEM/0MTeU/No4S3AvkyxWUakE6nG/NqOXUXP8 i6i3//a998s2OJeSHq+vi0JdOzBBQD5E5rjf6vfzlDFM17v0OqjiRA9lDNTZ5fN9xIDGmoIcF GCNwjBBBf6bYvw3Zf1njcUzOUN1sAiPdFW9H38zp8FMg87K/rJ7GubDPh0JojmA1+r9JGNkKk thDs8CtfK+oQGCJBs0/oxU6J6gZMa9HPVZkhMJJ4mCUwgJU1/e0b6iY5kDODXtJTMQiXSBOh5 Gnssn9m5BWaLoiE7iwUpn15qHPljw== X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.25 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 26 Dec 2017 17:22:18 -0000 --Sig_/Cvz1M0mb_N7h_yf_B8_YDGc Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Am Tue, 26 Dec 2017 11:44:29 -0500 Allan Jude schrieb: > On 2017-12-26 11:24, O. Hartmann wrote: > > Running recent CURRENT on most of our lab's boxes, I was in need to rep= lace and > > restore a ZFS RAIDZ pool. Doing so, I was in need to partition the disk= s I was about > > to replace. Well, the drives in question are 4k block size drives with = 512b emulation > > - as most of them today. I've created the only and sole partiton on eac= h 4 TB drive > > via the command sequence > >=20 > > gpart create -s GPT adaX > > gpart add -t freebsd-zfs -a 4k -l nameXX adaX > >=20 > > After doing this on all drives I was about to replace, something drove = me to check on > > the net and I found a lot of websites giving "advices", how to prepare = large, modern > > drives for ZFS. I think the GNOP trick is not necessary any more, but m= any blogs > > recommend to perform > >=20 > > gpart add -t freebsd-zfs -b 1m -a 4k -l nameXX adaX > >=20 > > to put the partition boundary at the 1 Megabytes boundary. I didn't do = that. My > > partitions all start now at block 40. > >=20 > > My question is: will this have severe performance consequences or is th= at negligible? > >=20 > > Since most of those websites I found via "zfs freebsd alignement" are f= rom years ago, > > I'm a bit confused now an consideration performing all this days-taking= resilvering > > process let me loose some more hair as the usual "fallout" ... > >=20 > > Thanks in advance, > >=20 > > Oliver > > =20 >=20 > The 1mb alignment is not required. It is just what I do to leave room > for the other partition types before the ZFS partition. >=20 > However, the replacement for the GNOP hack, is separate. In addition to > aligning the partitions to 4k, you have to tell ZFS that the drive is 4k: >=20 > sysctl vfs.zfs.min_auto_ashift=3D12 >=20 > (2^12 =3D 4096) >=20 > Before you create the pool, or add additional vdevs. >=20 I just checked with "zdb" what ashift is reported to my pool(s) and the res= ult claims to be "ashift: 12". --=20 O. Hartmann Ich widerspreche der Nutzung oder =C3=9Cbermittlung meiner Daten f=C3=BCr Werbezwecke oder f=C3=BCr die Markt- oder Meinungsforschung (=C2=A7 28 Abs.= 4 BDSG). --Sig_/Cvz1M0mb_N7h_yf_B8_YDGc Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- iLUEARMKAB0WIQQZVZMzAtwC2T/86TrS528fyFhYlAUCWkKCSAAKCRDS528fyFhY lF/0Af97Krwtkr9sM6lX8PzFBTBHQI+guJHkdZcViQDHRRH8nKJXf6F9MZj0lpKA FCVn1DkzpzRoIirwi/Dkwhl46Pr8AgCI7huGnhXuXOK6d8lurtr25A5nRAC6/LQJ Q/fzs/y6FGlr+2Q9gsNgMKu9C3qyxA4i+jOvbxlO3EZoBDw54CkS =5gGp -----END PGP SIGNATURE----- --Sig_/Cvz1M0mb_N7h_yf_B8_YDGc--