From owner-freebsd-fs Sat Nov 6 10:27:27 1999 Delivered-To: freebsd-fs@freebsd.org Received: from zed.ludd.luth.se (zed.ludd.luth.se [130.240.16.33]) by hub.freebsd.org (Postfix) with ESMTP id 61E5514EFE for ; Sat, 6 Nov 1999 10:27:24 -0800 (PST) (envelope-from pantzer@speedy.ludd.luth.se) Received: from speedy.ludd.luth.se (pantzer@speedy.ludd.luth.se [130.240.16.164]) by zed.ludd.luth.se (8.8.5/8.8.5) with ESMTP id TAA22113; Sat, 6 Nov 1999 19:27:21 +0100 Message-Id: <199911061827.TAA22113@zed.ludd.luth.se> X-Mailer: exmh version 2.0.1 12/23/97 To: Bernd Walter Cc: freebsd-fs@FreeBSD.ORG Subject: Re: RAID-5 and failure In-Reply-To: Message from Bernd Walter of "Sat, 06 Nov 1999 18:33:16 +0100." <19991106183316.A9420@cicely7.cicely.de> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Date: Sat, 06 Nov 1999 19:27:20 +0100 From: Mattias Pantzare Sender: owner-freebsd-fs@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org > If the system panics or power fails between such a write there is no wa= y to > find out if the parity is broken beside verifying the complete plex aft= er > reboot - the problem should be the same with all usual hard and softwar= e > solutions - greg already begun or finished recalculating and checking t= he > parity. This is realy a optimisation issue, if you just write without using two-phase commit then you have to recalculate parity after a powerfailure= =2E = (One might keep track of the regions of the disk that have had writes lat= ly = and only recalculate them) Or you do as it says under Two-phase commitment in http://www.sunworld.com/sunworldonline/swol-09-1995/swol-09-raid5-2.html.= To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message