From owner-freebsd-fs@FreeBSD.ORG Sun Mar 24 15:54:49 2013 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by hub.freebsd.org (Postfix) with ESMTP id F28B5446 for ; Sun, 24 Mar 2013 15:54:49 +0000 (UTC) (envelope-from jdc@koitsu.org) Received: from qmta06.emeryville.ca.mail.comcast.net (qmta06.emeryville.ca.mail.comcast.net [IPv6:2001:558:fe2d:43:76:96:30:56]) by mx1.freebsd.org (Postfix) with ESMTP id D7BE518C for ; Sun, 24 Mar 2013 15:54:49 +0000 (UTC) Received: from omta10.emeryville.ca.mail.comcast.net ([76.96.30.28]) by qmta06.emeryville.ca.mail.comcast.net with comcast id FStl1l0010cQ2SLA6Tupbu; Sun, 24 Mar 2013 15:54:49 +0000 Received: from koitsu.strangled.net ([67.180.84.87]) by omta10.emeryville.ca.mail.comcast.net with comcast id FTuo1l00V1t3BNj8WTupTA; Sun, 24 Mar 2013 15:54:49 +0000 Received: by icarus.home.lan (Postfix, from userid 1000) id CD7D773A1C; Sun, 24 Mar 2013 08:54:48 -0700 (PDT) Date: Sun, 24 Mar 2013 08:54:48 -0700 From: Jeremy Chadwick To: Quartz Subject: Re: ZFS question Message-ID: <20130324155448.GA4122@icarus.home.lan> References: <20130321044557.GA15977@icarus.home.lan> <514AA192.2090006@sneakertech.com> <20130321085304.GB16997@icarus.home.lan> <20130324153342.GA3687@icarus.home.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130324153342.GA3687@icarus.home.lan> User-Agent: Mutt/1.5.21 (2010-09-15) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net; s=q20121106; t=1364140489; bh=iNs4SGQ9HJweXQCfM6xL6Sh20a59ezADV4/ilKNhBU0=; h=Received:Received:Received:Date:From:To:Subject:Message-ID: MIME-Version:Content-Type; b=Dt4J+CAdfXfFNX7pID8mF2h5fXPtjbAinTY23giphVPK09NHwE7IaORbMTVj+Qah5 tl2cvzp3AX3N0kah/cbheLTdIWVi3V8rWrX354Y5d0jsMrgHTdCV35XEOyMFzOyiWw 59S/5Mxofv9CYVl4XzMAF6/w6ORtCzRzZmJUrvzySCNC0YWeiLHOuqQm7yll6DIvX2 W9qrGg/lyuS71gtel1QduOTKz4pPTjvQHLJP4hFrqw2hI/nKbazBfDKNj+XGIhiNg6 58Y6YTa3GiTSwWDKrZJNP+IftYTCGmSjSm2Kykpkx8JqLM/I+N1fm9plpHNIntxdVb edf93HDELtaAw== Cc: freebsd-fs@freebsd.org X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 24 Mar 2013 15:54:50 -0000 On Sun, Mar 24, 2013 at 08:33:42AM -0700, Jeremy Chadwick wrote: > However, commands like "zpool status" ...and seems a typo I made in vim caused the rest of my sentence to get deleted before I sent it out. This should have read: > However, commands like "zpool status" work just fine, but things like > "zpool destroy" and so on indefinitely block ("mount drain"), which to > me makes some degree of sense. To expand: for example, you've lost 3 disks of a 4-disk raidz2 pool, your data is buggered and you'll need to recover from backups. Yes, you will need to reboot for the ZFS layer to effectively "un-wedge" itself from whatever catatonic state its in. No argument: this is a bug somewhere, and my guess is that it relates to the confused state of the devices in CAM-land. But regardless, I think if you were to lose 3 of 4 disks on a raidz2 pool you'd have much more serious things to be worried about than "well crap I have to issue a reboot". And yes, I did test a reboot in the scenario I described -- the system did reboot without physically pressing the button. But then again, for remotely-managed systems, administrators should have the ability to remotely power-cycle or force resets (e.g. drop to DDB via serial console and force a reset). People who run servers remotely yet lack this capability are intentionally choosing to live dangerously and I do not condone such. These folks also make me wonder how they update world without remote console access, since to do it right you *must* drop to single-user for the installworld phase. I learned my lesson of "assuming" installworld would work from multi-user long ago when it broke one time and I ended up with a system with broken /libexec/ld-elf* binaries. Having to go to the datacenter 30 minutes away at 3 in the morning taught me to follow instructions. -- | Jeremy Chadwick jdc@koitsu.org | | UNIX Systems Administrator http://jdc.koitsu.org/ | | Mountain View, CA, US | | Making life hard for others since 1977. PGP 4BD6C0CB |