From owner-freebsd-fs@FreeBSD.ORG Sun Jan 27 13:48:11 2013 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id A2B037F3 for ; Sun, 27 Jan 2013 13:48:11 +0000 (UTC) (envelope-from pawel@dawidek.net) Received: from mail.dawidek.net (garage.dawidek.net [91.121.88.72]) by mx1.freebsd.org (Postfix) with ESMTP id 6FF2FE4 for ; Sun, 27 Jan 2013 13:48:10 +0000 (UTC) Received: from localhost (89-73-195-149.dynamic.chello.pl [89.73.195.149]) by mail.dawidek.net (Postfix) with ESMTPSA id 12CC2B0A; Sun, 27 Jan 2013 14:45:31 +0100 (CET) Date: Sun, 27 Jan 2013 14:48:46 +0100 From: Pawel Jakub Dawidek To: Laurence Gill Subject: Re: HAST performance overheads? Message-ID: <20130127134845.GC1346@garage.freebsd.pl> References: <20130125121044.1afac72e@googlemail.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="WplhKdTI2c8ulnbP" Content-Disposition: inline In-Reply-To: <20130125121044.1afac72e@googlemail.com> X-OS: FreeBSD 10.0-CURRENT amd64 User-Agent: Mutt/1.5.21 (2010-09-15) Cc: freebsd-fs@freebsd.org X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 27 Jan 2013 13:48:11 -0000 --WplhKdTI2c8ulnbP Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Jan 25, 2013 at 12:10:44PM +0000, Laurence Gill wrote: > If I create ZFS raidz2 on these... >=20 > - # zpool create pool raidz2 da0 da1 da2 da3 da4 da5 >=20 > Then run a dd test, a sample output is... >=20 > - # dd if=3D/dev/zero of=3Dtest.dat bs=3D1M count=3D1024 > 1073741824 bytes transferred in 7.689634 secs (139634974 bytes/sec) >=20 > - # dd if=3D/dev/zero of=3Dtest.dat bs=3D16k count=3D65535 > 1073725440 bytes transferred in 1.909157 secs (562408130 bytes/sec) >=20 > This is much faster than compared to running hast, I would expect an > overhead, but not this much. For example: >=20 > - # hastctl create disk0/disk1/disk2/disk3/disk4/disk5 > - # hastctl role primary all > - # zpool create pool raidz2 disk0 disk1 disk2 disk3 disk4 disk5 >=20 > Run a dd test, and the speed is... >=20 > - # dd if=3D/dev/zero of=3Dtest.dat bs=3D1M count=3D1024 > 1073741824 bytes transferred in 40.908153 secs (26247624 bytes/sec) >=20 > - # dd if=3D/dev/zero of=3Dtest.dat bs=3D16k count=3D65535 > 1073725440 bytes transferred in 42.017997 secs (25553942 bytes/sec) Let's try to test one step at a time. Can you try to compare sequential performance of regular disk vs. HAST with no secondary configured? By no secondary configured I mean 'remote' set to 'none'. Just do: # dd if=3D/dev/zero of=3D/dev/da0 bs=3D1m count=3D10240 then configure HAST and: # dd if=3D/dev/zero of=3D/dev/hast/disk0 bs=3D1m count=3D10240 Which FreeBSD version is it? PS. Your ZFS tests are pretty meaningless, because it is possible that everything will end up in memory. I'm sure this is what happens in 'bs=3D16k count=3D65535' case. Let try raw providers first. --=20 Pawel Jakub Dawidek http://www.wheelsystems.com FreeBSD committer http://www.FreeBSD.org Am I Evil? Yes, I Am! http://tupytaj.pl --WplhKdTI2c8ulnbP Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.19 (FreeBSD) iEYEARECAAYFAlEFMD0ACgkQForvXbEpPzRMigCglS8ZP9RggVl0MfVk+A25xgd2 29wAnigH5gA4RXxKI/4XLfKT8sW9eoPP =D2zj -----END PGP SIGNATURE----- --WplhKdTI2c8ulnbP--