From owner-freebsd-questions@FreeBSD.ORG Sat Feb 19 21:52:45 2011 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 27F0C106564A for ; Sat, 19 Feb 2011 21:52:45 +0000 (UTC) (envelope-from DStaal@usa.net) Received: from mail.magehandbook.com (173-8-4-45-WashingtonDC.hfc.comcastbusiness.net [173.8.4.45]) by mx1.freebsd.org (Postfix) with ESMTP id F05628FC15 for ; Sat, 19 Feb 2011 21:52:44 +0000 (UTC) Received: from [192.168.1.50] (Mac-Pro.magehandbook.com [192.168.1.50]) by mail.magehandbook.com (Postfix) with ESMTP id DAFE02845B; Sat, 19 Feb 2011 16:52:43 -0500 (EST) Date: Sat, 19 Feb 2011 16:52:43 -0500 From: Daniel Staal To: Robert Bonomi , freebsd-questions@freebsd.org Message-ID: In-Reply-To: <201102192012.p1JKCKnP038248@mail.r-bonomi.com> References: <201102192012.p1JKCKnP038248@mail.r-bonomi.com> X-Mailer: Mulberry/4.0.8 (Mac OS X) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline Cc: Subject: Re: ZFS-only booting on FreeBSD X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: FreeBSD Questions List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 19 Feb 2011 21:52:45 -0000 --As of February 19, 2011 2:12:20 PM -0600, Robert Bonomi is alleged to have said: > A non-ZFS boot drive results in immediate, _guaranteed_, down-time for > replacement if/when it fails. > > A ZFS boot drive lets you replace the drive and *schedule* the down-time > (for a 'test' re-boot, to make *sure* everything works) at a convenient > time. --As for the rest, it is mine. No it doesn't. It only extends the next scheduled downtime until you deal with it. ;) (Or, in a hot-swap environment with sufficient monitoring, means you need to deal with it before the next scheduled downtime.) Or, from what it sounds like, you could have a redundant/backup boot disk. I'm planning on using a $5 USB drive as my boot disk. Triple redundancy would cost $15. I paid more for lunch today. (Hmm. I'll have to test to see if that setup works, although given the rest of this discussion I don't see why it shouldn't...) I see the advantage, and that it offers higher levels of resiliency and if properly handled should cause no problems. I just hate relying on humans to remember things and follow directions. That's what computers are for. Repairing a failed disk in a ZFS boot pool requires a human to remember to look for directions in an unusual place, and then follow them correctly. If they don't, nothing happens immediately, but there is the possibility of failure at some later unspecified time. (Meanwhile if they look for directions in the *usual* place, they get a simple and straightforward set of instructions that will appear to work.) *If* that failure occurs, that downtime will be longer than the downtime you would save from a dozen boxes being handled using the correct ZFS procedure, as everyone tears their hair out going 'Why doesn't it work?!? It worked just fine a moment ago!' until someone remembers this quirk. I don't like quirky computers. That's why I'm not a Windows admin. ;) Daniel T. Staal --------------------------------------------------------------- This email copyright the author. Unless otherwise noted, you are expressly allowed to retransmit, quote, or otherwise use the contents for non-commercial purposes. This copyright will expire 5 years after the author's death, or in 30 years, whichever is longer, unless such a period is in excess of local copyright law. ---------------------------------------------------------------