From owner-freebsd-hackers@FreeBSD.ORG Sun May 31 22:13:23 2009 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 982671065673 for ; Sun, 31 May 2009 22:13:23 +0000 (UTC) (envelope-from kraduk@googlemail.com) Received: from ey-out-2122.google.com (ey-out-2122.google.com [74.125.78.25]) by mx1.freebsd.org (Postfix) with ESMTP id 1653B8FC2E for ; Sun, 31 May 2009 22:13:22 +0000 (UTC) (envelope-from kraduk@googlemail.com) Received: by ey-out-2122.google.com with SMTP id 22so299495eye.7 for ; Sun, 31 May 2009 15:13:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=domainkey-signature:received:received:from:to:cc:references:subject :date:message-id:mime-version:content-type:content-transfer-encoding :x-mailer:in-reply-to:x-mimeole:thread-index; bh=AT/bcruC/6/+J2ppumS9emcaTlYGPL8+0NnLQ04bpGI=; b=YD8cgmXf5G3Lr2t7Q7VuKJ2r4IB0eVsEBfMFYPPPoV2vaW47Xm4vSlqAywnBij8kU5 gVayrT2Wpra2MLdNT3Jx8Uf8IvYWeRtLuu9JODtFAWV6qKvnce+fKRYsQucwyLrifzMh SMyZ17MGn6Z7rHhSv3ekUqSesptF4Ya0oh4f0= DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=from:to:cc:references:subject:date:message-id:mime-version :content-type:content-transfer-encoding:x-mailer:in-reply-to :x-mimeole:thread-index; b=hGvLJSAnIkbLMpPMusI6l1YmgSriyN3t3kdITpg2kRkruKyai1v4YcT7+pEsxxk0gV Rb4DWqemWHZk8k9iykz8Vh+FYh9xWkgRV6ymSE53izflvMjBiT1d1D3xtVKpXCJoqYqU vBm/z330IGH5Qs3/VsLAhlipd1tIoKjVcdU9E= Received: by 10.210.88.7 with SMTP id l7mr5567728ebb.74.1243808002121; Sun, 31 May 2009 15:13:22 -0700 (PDT) Received: from LTPCSCOTT (e1-1.ns500-1.ts.milt.as9105.net [212.74.112.53]) by mx.google.com with ESMTPS id 4sm6047998ewy.104.2009.05.31.15.13.21 (version=SSLv3 cipher=RC4-MD5); Sun, 31 May 2009 15:13:21 -0700 (PDT) From: krad To: "'Wojciech Puchar'" , References: <20090530175239.GA25604@logik.internal.network> <20090530144354.2255f722@bhuda.mired.org> <20090530191840.GA68514@logik.internal.network> <20090530162744.5d77e9d1@bhuda.mired.org> <20090531201445.GA82420@logik.internal.network> Date: Sun, 31 May 2009 23:13:19 +0100 Message-ID: <0229B3BF1BE94C82AA11FD06CBE0BDEF@uk.tiscali.intl> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit X-Mailer: Microsoft Office Outlook 11 In-Reply-To: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 Thread-Index: AcniOtBzjr39Q7HmRUe7nxzsAsJm2QAAXP/g X-Mailman-Approved-At: Mon, 01 Jun 2009 00:17:37 +0000 Cc: freebsd-hackers@freebsd.org, 'krad' Subject: RE: Request for opinions - gvinum or ccd? X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 31 May 2009 22:13:23 -0000 Yep, its also worth noting that with the capacities of drives these days you should really use raidz2 in zfs (or some double parity raid on other systems) if you are worried about data integrity. The reason being the odds of the crc checking not detecting an error are much more likely these days. The extra layer of parity pushes these odds into being much bigger -----Original Message----- From: Wojciech Puchar [mailto:wojtek@wojtek.tensor.gdynia.pl] Sent: 31 May 2009 22:57 To: xorquewasp@googlemail.com Cc: krad; freebsd-hackers@freebsd.org Subject: Re: Request for opinions - gvinum or ccd? >> Would create a striped data set across da1 and da2 > > What kind of performance gain can I expect from this? I'm purely thinking > about performance now - the integrity checking stuff of ZFS is a pleasant > extra. with stripping - as much as with gstripe, ZFS do roughly the same. with RAID-z - faster transfer, rougly same IOps as single disk. After i read ZFS papers i know that RAID-z is actually more like RAID-3 not RAID-5.