From owner-freebsd-questions@FreeBSD.ORG Mon Jan 27 13:56:23 2014 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id D48C86AD for ; Mon, 27 Jan 2014 13:56:23 +0000 (UTC) Received: from mail-we0-x236.google.com (mail-we0-x236.google.com [IPv6:2a00:1450:400c:c03::236]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 6563A1A77 for ; Mon, 27 Jan 2014 13:56:23 +0000 (UTC) Received: by mail-we0-f182.google.com with SMTP id w62so5212804wes.41 for ; Mon, 27 Jan 2014 05:56:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; bh=0WoikG3pRvoIFqDrr2g+LcZtlRgSf6bmvUnYfsiolcM=; b=gcEXpsbWbHdLc2IIPVHYA50SVPJ4RMTcjZF8OtgrtYN5xShoxFlmj82aMRMZbMShn3 V3jTW8C6lphCC5WrhyEohj9zCCWqIQfkt1zBInZTWv4EbBb2VJkH63+qByrRVrToKYpy 6Qg3eGAypQpAvtptA/V670R2mLx84W2xqYaR5oI4CoJY0uwWgsazabrnxuTwyiIiWVQ1 STFQOs96Dlc64i4NQrsGlroVg8Z41NZtPvZ5clNfcXUBQRMRaZn5mOYggP9flrxtkV0Z aRt2e1koucvPrsIfL4CvaRhOwWXsHPwtOm48EoJ5BzAH0zFSY9mObNbYzpZdKN0V16d/ APTg== X-Received: by 10.180.188.197 with SMTP id gc5mr11995037wic.30.1390830981802; Mon, 27 Jan 2014 05:56:21 -0800 (PST) Received: from x220.optiplex-networks.com (81-178-2-118.dsl.pipex.com. [81.178.2.118]) by mx.google.com with ESMTPSA id fm3sm25430798wib.8.2014.01.27.05.56.20 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Mon, 27 Jan 2014 05:56:21 -0800 (PST) Message-ID: <52E6657E.1050103@gmail.com> Date: Mon, 27 Jan 2014 13:56:14 +0000 From: Kaya Saman User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: krad Subject: Re: ZFS confusion References: <52E40C82.7050302@gmail.com> <52E62DFF.3010600@gmail.com> <52E6463C.6090805@gmail.com> <52E6537F.8020907@gmail.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-questions , =?ISO-8859-1?Q?Trond_Endrest=F8l?= X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.17 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 27 Jan 2014 13:56:23 -0000 Many thanks for the explanation :-) On 01/27/2014 01:13 PM, krad wrote: > Neither of these setups is ideal, The best practice for your vdev is > to use 2^n + your parity drives > This means in your case with raidz3 you would do something > > 2 + 3 > 4 + 3 > 8 + 3 > > the 1st two are far from ideal as the ratios are low 8 + 3, so 11 > drives per raidz3 vdev would be optimal. This would fit nicely with > your 26 drive enclosure as you would use 2x11 drive raidz3 vdevs, 2 > hot spares, and two devices left for l2arc/zil. Probably best chop up > the ssds, mirror the zil and stripe the l2arc, assuming you dont want > to do down the route using generic SSD's rather than write/read > optimized ones Yep was going to use your suggestion for l2arc/zil on 2x 128GB Corsair Force Series GS, 2.5" which have quite good w/r speeds - also I use these on other servers which tend to be quite good and reliable. I think the way to create a mirrored zil and stiped l2arc would be to use GPT to partition the drives, then use the zfs features across the partitions. Hmm.... so it also looks like I'm gona have to wait a while for some more drives then in order to create an 11 disk raidz3 pool. But at least things will be done properly and in a good manner rather then going down a patch with "no return". > > Regards, Kaya