From owner-freebsd-fs@FreeBSD.ORG Sat Sep 20 18:53:17 2008 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id B1E47106566C for ; Sat, 20 Sep 2008 18:53:17 +0000 (UTC) (envelope-from yalur@mail.ru) Received: from mx4.mail.ru (fallback.mail.ru [194.67.57.14]) by mx1.freebsd.org (Postfix) with ESMTP id 696DF8FC0A for ; Sat, 20 Sep 2008 18:53:17 +0000 (UTC) (envelope-from yalur@mail.ru) Received: from mx39.mail.ru (mx39.mail.ru [194.67.23.35]) by mx4.mail.ru (mPOP.Fallback_MX) with ESMTP id 841ECABB44 for ; Sat, 20 Sep 2008 22:35:24 +0400 (MSD) Received: from [93.73.134.74] (port=4480 helo=scrupulous.sifter.volia.net) by mx39.mail.ru with asmtp id 1Kh7Ig-0002RP-00 for freebsd-fs@freebsd.org; Sat, 20 Sep 2008 22:35:22 +0400 From: Ruslan Kovtun Organization: Home To: freebsd-fs@freebsd.org Date: Sat, 20 Sep 2008 21:35:20 +0300 User-Agent: KMail/1.9.7 References: <48D4C2AA.8080000@modulus.org> In-Reply-To: <48D4C2AA.8080000@modulus.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline Message-Id: <200809202135.20730.yalur@mail.ru> X-Spam: Not detected X-Mras: OK X-Mailman-Approved-At: Sat, 20 Sep 2008 21:27:44 +0000 Subject: Re: zfs benchmarks and 7 disk raidz oddity X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: yalur@mail.ru List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 20 Sep 2008 18:53:17 -0000 Hi. Thank you very much, very useful information.=20 It is interesting when we can use this on 7.x? =D0=92 =D1=81=D0=BE=D0=BE=D0=B1=D1=89=D0=B5=D0=BD=D0=B8=D0=B8 =D0=BE=D1=82 = =D0=A1=D1=83=D0=B1=D0=B1=D0=BE=D1=82=D0=B0 20 =D1=81=D0=B5=D0=BD=D1=82=D1= =8F=D0=B1=D1=80=D1=8F 2008 Andrew Snow =D0=BD=D0=B0=D0=BF=D0=B8=D1=81=D0=B0= =D0=BB(a): > Hi all, > > I am running 8-CURRENT with ZFS patches on a 3ghz Core2Duo with Intel > P45 chipset. I took some benchmarks of ZFS on six old SATA disks and > one PATA, onboard controllers only, and I expect you are interested to > see the results. The disks range in size from 200gb to 320gb. > > I tried several configurations with quick and dirty testing. Listed > below is the sequential megabytes/sec rating as measured by dd bs=3D1m for > a 10GB file. All ZFS settings were left at their defaults. > > > Conf Write Read (MB/s) > ------------------------------------ > 7 disk RAIDZ2 220 305 > 7 disk RAIDZ1 84 361 > 7 disk striped 318 409 > 7 disk stripe copies=3D2 140 164 > > 6 disk RAIDZ2 173 260 > 6 disk RAIDZ1 238 307 > 6 disk striped 280 346 > 6 disk 2xRAIDZ1 striped 188 251 > 6 disk striped mirrors 164 323 > 6 disk stripe copies=3D2 151 179 > > > A few notes: > > 1. using copies=3D2 is a nice way to be able to get RAID1-like mirroring > reliability but on an odd number of disks. However you take a > noticeable performance penalty: Write speed is fine but read speed is > almost half of what RAID0+1 achieved. > > 2. RAIDZ1 and RAIDZ2 are fast and efficient. However in total it caused > the system to use almost all of one CPU core during writing. > > 3. There seemed to be a bug with 7 disks and RAIDZ1 - the write > performance was terrible! When I ran "gstat" I noticed it was spending > much time writing to only two disks most of the time, which became a > serious bottleneck - the worst write score of the lot. Read was fine. > Perhaps the algorithm isn't optimised for choosing parity locations out > of exactly 7 disks? > > > > - Andrew > > _______________________________________________ > freebsd-fs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" =2D-=20 ________________ Ruslan Kovtun=20 mailto: yalur@mail.ru mob: +380503557878, +380919015095 ICQ: 277696182