From owner-freebsd-hackers Fri Mar 24 10:52:27 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from bingnet2.cc.binghamton.edu (mailbox.adm.binghamton.edu [128.226.10.60]) by hub.freebsd.org (Postfix) with ESMTP id B3B2C37B74A; Fri, 24 Mar 2000 10:52:19 -0800 (PST) (envelope-from zzhang@cs.binghamton.edu) Received: from sol.cs.binghamton.edu (sol.cs.binghamton.edu [128.226.123.100]) by bingnet2.cc.binghamton.edu (8.9.3/8.9.3) with SMTP id NAA00657; Fri, 24 Mar 2000 13:52:18 -0500 (EST) Date: Fri, 24 Mar 2000 11:27:25 -0500 (EST) From: Zhihui Zhang Reply-To: Zhihui Zhang To: Mike Smith Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: Software RAID and vinum In-Reply-To: <200003241826.KAA00964@mass.cdrom.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Fri, 24 Mar 2000, Mike Smith wrote: > > > > I searched the mailing list archive. I am not sure whether Vinum has > > solved the problem of atomic writes in a stripe to both the data fragment > > and parity fragment (RAID 5). In the case of a crash, you have no idea of > > where the writes have finished (even worse, a fragment may contain > > several sectors). > > This problem can't be solved with software-only RAID, and no (sensible) > software RAID implementation attempts to deal with it. Software RAID > reliability is predicated on the correct functioning of the system; it's > there to provide fault tolerance for the high-failure-rate hardware (eg. > disks). Thanks. It seems to me that you are saying software RAID can NOT cope with system crash and power failure? What about the Zebra filesystem or something like two-phase commit? -Zhihui To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message