From owner-freebsd-fs@FreeBSD.ORG Sat Mar 26 21:46:51 2011 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id A57FF106564A for ; Sat, 26 Mar 2011 21:46:51 +0000 (UTC) (envelope-from alexander@leidinger.net) Received: from mail.ebusiness-leidinger.de (mail.ebusiness-leidinger.de [217.11.53.44]) by mx1.freebsd.org (Postfix) with ESMTP id 64CA28FC17 for ; Sat, 26 Mar 2011 21:46:51 +0000 (UTC) Received: from outgoing.leidinger.net (p5B15623C.dip.t-dialin.net [91.21.98.60]) by mail.ebusiness-leidinger.de (Postfix) with ESMTPSA id AAB95844015; Sat, 26 Mar 2011 22:46:46 +0100 (CET) Received: from unknown (IO.Leidinger.net [192.168.2.110]) by outgoing.leidinger.net (Postfix) with ESMTP id 0E5E6159E; Sat, 26 Mar 2011 22:46:44 +0100 (CET) Date: Sat, 26 Mar 2011 22:46:44 +0100 From: Alexander Leidinger To: Anders Andersson Message-ID: <20110326224644.00006d6b@unknown> In-Reply-To: References: X-Mailer: Claws Mail 3.7.8cvs47 (GTK+ 2.16.6; i586-pc-mingw32msvc) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-EBL-MailScanner-Information: Please contact the ISP for more information X-EBL-MailScanner-ID: AAB95844015.AF0D7 X-EBL-MailScanner: Found to be clean X-EBL-MailScanner-SpamCheck: not spam, spamhaus-ZEN, SpamAssassin (not cached, score=-1, required 6, autolearn=disabled, ALL_TRUSTED -1.00) X-EBL-MailScanner-From: alexander@leidinger.net X-EBL-MailScanner-Watermark: 1301780807.59233@8+JZ+t5kJ9C7kZNYwi07oQ X-EBL-Spam-Status: No Cc: freebsd-fs@freebsd.org Subject: Re: RAID-Z in a disk-failure. X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 26 Mar 2011 21:46:51 -0000 On Sat, 26 Mar 2011 15:42:57 +0100 Anders Andersson wrote: > Evening! I have a question about ZFS in a FreeBSD setting, more > specifically about RAID-Z. I have never used ZFS so I might have > misunderstood something, but imagine this situation: > > You're using ZFS in RAID-Z with 4 disks. One of these gets a > catastrophic failure. You replace the disk with a new one, but when > the RAID-Z is rebuilt, the software notices that one sector/block on > another disk has become corrupted. It notices this because ZFS keeps a > checksum. > > What happens then? Since the redundancy is temporarily disabled > because of the failed disk, this sector/block is nowhere to be found. > My hope is that the system will handle this gracefully, so that only > the file using this block will be unreadable, but the rest of the data > is available and can be rebuilt. The worst that could happen is that > the rebuild is refused and the whole pool is gone. > > Have I missed something in this scenario? If a corruption can not be corrected, tt's only the file (or directory-subtree) with this corruption which is unreadable. Bye, Alexander. -- http://www.Leidinger.net Alexander @ Leidinger.net: PGP ID = B0063FE7 http://www.FreeBSD.org netchild @ FreeBSD.org : PGP ID = 72077137