From owner-freebsd-stable Fri Apr 12 11:19:17 1996 Return-Path: owner-stable Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id LAA23840 for stable-outgoing; Fri, 12 Apr 1996 11:19:17 -0700 (PDT) Received: from itsdsv1.enc.edu (itsdsv1.enc.edu [199.93.252.241]) by freefall.freebsd.org (8.7.3/8.7.3) with SMTP id LAA22992 Fri, 12 Apr 1996 11:09:11 -0700 (PDT) Received: from dingo.enc.edu (dingo.enc.edu [199.93.252.229]) by itsdsv1.enc.edu (8.6.12/8.6.9) with SMTP id OAA02835; Fri, 12 Apr 1996 14:08:24 -0400 Date: Fri, 12 Apr 1996 14:11:32 -0400 (EDT) From: Charles Owens To: Satoshi Asami cc: stable@FreeBSD.ORG, SCSI@FreeBSD.ORG Subject: Re: Disk Mirroring In-Reply-To: <199604102312.QAA19403@sunrise.cs.berkeley.edu> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-stable@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk On Wed, 10 Apr 1996, Satoshi Asami wrote: > * Is there a way to mirror two disks in FreeBSD? The two different > * possibilities are at the driver layer or at the filesystem layer. > * I imagine the driver layer would be the easiest. Just take the > * block to be written and write it out to both disks. The reason I > * suggest the filesystem layer is to avoid duplicating the swap space > * on both disks. It would be cool if the boot code could > * automatically deal with either disk failing and still having the > * system boot. Naturally, the driver should be able to deal with > * either disk failing. Has anyone given this some thought? With > * disks getting real cheap, it is a good way to have some fault > * tolerance with out the cost or performance hit of RAID. (Actually, > * I think mirroring is one form of RAID.) > > There is a driver called "ccd" (concatenated disk) that I ported from > NetBSD. It is designed primarily for striping disk arrays but it has > mirror support so you can use it to mirror partitions by just making > it a mirrored 2-disk array. :) > > Please take a look at > > http://stampede.cs.berkeley.edu/ccd/ > > for details. I'm planning to put it into -current soon but there's a > 2.1R version too. > Any chance that you'll do a -stable version anytime soon? --- ------------------------------------------------------------------------- Charles Owens Email: owensc@enc.edu "I read somewhere to learn is to Information Technology Services remember... and I've learned that Eastern Nazarene College we've all forgot..." - King's X -------------------------------------------------------------------------