From owner-freebsd-stable@FreeBSD.ORG Sat Jul 11 20:07:54 2009 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id EE2CA106564A for ; Sat, 11 Jul 2009 20:07:54 +0000 (UTC) (envelope-from fjwcash@gmail.com) Received: from mail-yx0-f181.google.com (mail-yx0-f181.google.com [209.85.210.181]) by mx1.freebsd.org (Postfix) with ESMTP id A3FB38FC08 for ; Sat, 11 Jul 2009 20:07:54 +0000 (UTC) (envelope-from fjwcash@gmail.com) Received: by yxe11 with SMTP id 11so2737999yxe.3 for ; Sat, 11 Jul 2009 13:07:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type; bh=q1M4tkMJ54NwLsx5cUrvx9dWsdX2CQkp2RI+93rVKhA=; b=T082m1PJlsg1BM68AM6zE8UrsfpLv4HsD3w74q0gzzcsUUO6vxYNIfHfyKboGzjlnD G2OPugoI7BdIl11GmyeCiCmHvStwn1aY387VIrSeEZUS+EfFLny4E8AzarMqQx9wBtoB b+F1pl8m4dF8GRBwNl4gJPeMzi6liTyJLCOsc= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=QPdDOQSiSXfg9fMa8anQAdsJL9XD5kZpBrDNBpI67nZ4Z9A49V6SNlxX3IvCzRhfan hmt0+mLbR1S7hkj1MySF0SVmTwvMsb6o5nOgcsv4cWY963Lv87oS2pdW1cx0TUzF3Z5w c5ap5uQkblvmc26vQPrR7WwWJ2dbE+xzCe/lA= MIME-Version: 1.0 Received: by 10.151.155.5 with SMTP id h5mr5387702ybo.259.1247342873817; Sat, 11 Jul 2009 13:07:53 -0700 (PDT) In-Reply-To: <20090711084042.GA77702@server.vk2pj.dyndns.org> References: <20090709112512.GA44158@hugo10.ka.punkt.de> <73a41d4b72d62b0bfe3d0fb7206376a8.squirrel@cygnus.homeunix.com> <84665df87e93a6ccf24d9837cbc53eba.squirrel@cygnus.homeunix.com> <20090711084042.GA77702@server.vk2pj.dyndns.org> Date: Sat, 11 Jul 2009 13:07:52 -0700 Message-ID: From: Freddie Cash To: freebsd-stable@freebsd.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Subject: Re: ZFS - thanks X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 11 Jul 2009 20:07:55 -0000 On Sat, Jul 11, 2009 at 1:40 AM, Peter Jeremy wrote: > On 2009-Jul-09 15:39:35 +0300, Dan Naumov wrote: > >A single 40 disk raidz (DO NOT DO THIS) will have 40 disks total, 39 > >disks worth of space and will definately explode on you sooner rather > >than later (probably on the first import, export or scrub). > > Can you provide a reference for this statement. AFAIK, the only > reason for the upper recommended limit of 9 disks is performance. > We found it impossible to re-silver a new/replacement drive in a 24-drive raidz2 vdev. Even after almost two weeks of trying, it never got above 20-30% complete before restarting. That led me to do a bunch of web searches, and found several blogs by Sun people that went over how the raidz implementation works, what the limitations are (limited to the IOps of a single drive), and the recommendation to never use more than 8 or 9 drives in any single vdev. -- Freddie Cash fjwcash@gmail.com