From owner-freebsd-fs@FreeBSD.ORG  Sat May 23 13:04:06 2009
Return-Path: <owner-freebsd-fs@FreeBSD.ORG>
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 C20C910656B7
	for <freebsd-fs@freebsd.org>; Sat, 23 May 2009 13:04:06 +0000 (UTC)
	(envelope-from randy@psg.com)
Received: from ran.psg.com (ran.psg.com [IPv6:2001:418:1::36])
	by mx1.freebsd.org (Postfix) with ESMTP id 9E5AD8FC12
	for <freebsd-fs@freebsd.org>; Sat, 23 May 2009 13:04:06 +0000 (UTC)
	(envelope-from randy@psg.com)
Received: from localhost ([127.0.0.1] helo=rmac.psg.com)
	by ran.psg.com with esmtp (Exim 4.69 (FreeBSD))
	(envelope-from <randy@psg.com>)
	id 1M7qtR-000Ekp-Dv; Sat, 23 May 2009 13:04:05 +0000
Received: from rmac.local.psg.com (localhost [127.0.0.1])
	by rmac.psg.com (Postfix) with ESMTP id 3AE1D1963BEA;
	Sat, 23 May 2009 06:04:05 -0700 (PDT)
Date: Sat, 23 May 2009 06:04:04 -0700
Message-ID: <m27i08km2j.wl%randy@psg.com>
From: Randy Bush <randy@psg.com>
To: Artis Caune <artis.caune@gmail.com>
In-Reply-To: <9e20d71e0905230537ibcaf852g1dc32b6ffc3a681d@mail.gmail.com>
References: <m28wkon90c.wl%randy@psg.com>
	<9e20d71e0905230537ibcaf852g1dc32b6ffc3a681d@mail.gmail.com>
User-Agent: Wanderlust/2.15.5 (Almost Unreal) SEMI/1.14.6 (Maruoka)
	FLIM/1.14.9 (=?ISO-8859-4?Q?Goj=F2?=) APEL/10.7 Emacs/22.3
	(i386-apple-darwin9.6.0) MULE/5.0 (SAKAKI)
MIME-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka")
Content-Type: text/plain; charset=US-ASCII
Cc: freebsd-fs <freebsd-fs@freebsd.org>
Subject: Re: raidz2 a bit big
X-BeenThere: freebsd-fs@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Filesystems <freebsd-fs.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-fs>,
	<mailto:freebsd-fs-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-fs>
List-Post: <mailto:freebsd-fs@freebsd.org>
List-Help: <mailto:freebsd-fs-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-fs>,
	<mailto:freebsd-fs-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Sat, 23 May 2009 13:04:08 -0000

>>    NAME    STATE   READ WRITE CKSUM
>>    tank    ONLINE    0   0   0
>>     raidz2  ONLINE    0   0   0
>>      da0s3  ONLINE    0   0   0
>>      da1s3  ONLINE    0   0   0
>>      da2s1  ONLINE    0   0   0
>>      da3s1  ONLINE    0   0   0
>>      da4s1  ONLINE    0   0   0
>>      da5s1  ONLINE    0   0   0
>>      da6s1  ONLINE    0   0   0
>>      da7s1  ONLINE    0   0   0
>>      da8s1  ONLINE    0   0   0
>>      da9s1  ONLINE    0   0   0
>>      da10s1 ONLINE    0   0   0
>>      da11s1 ONLINE    0   0   0
> 
> Reads on such configurations are very slow.

how are writes?

> If one of your disk, for example, is capable of 100 IO per/sec, then:
> with 12 disks in one raidz2 vdev you get only 100 IOPS
> with 4 disks in raidz2 (total 3 raidz2 vdevs) you get 300 IOPS
> with 2 disks in mirror (total 6 mirror vdevs) you can get 1200 IOPS

ok.  sounds nice.  but then, don't i have six file systems and have to
start playing lay-out design games?

randy