From owner-freebsd-scsi Sat Sep 28 12:59:22 1996 Return-Path: owner-freebsd-scsi Received: (from root@localhost) by freefall.freebsd.org (8.7.5/8.7.3) id MAA09418 for freebsd-scsi-outgoing; Sat, 28 Sep 1996 12:59:22 -0700 (PDT) Received: from al.imforei.apana.org.au (pjchilds@al.imforei.apana.org.au [202.12.89.41]) by freefall.freebsd.org (8.7.5/8.7.3) with ESMTP id MAA09344 for ; Sat, 28 Sep 1996 12:59:15 -0700 (PDT) Received: (from pjchilds@localhost) by al.imforei.apana.org.au (8.8.0/8.7.3) id FAA23341; Sun, 29 Sep 1996 05:29:13 +0930 (CST) Date: Sun, 29 Sep 1996 05:29:13 +0930 (CST) From: Peter Childs Message-Id: <199609281959.FAA23341@al.imforei.apana.org.au> To: bsdscsi@shadows.aeon.net (mika ruohotie), freebsd-scsi@freebsd.org Subject: Re: striping/mirroring? X-Newsreader: TIN [version 1.2 PL2] Sender: owner-freebsd-scsi@freebsd.org X-Loop: FreeBSD.org Precedence: bulk : > Thus if you were to mirror a 4 drive combination to a single drive, that : > drive would have to be 4 times as large. It would also need to be fast. : it should be huge, yes. fast, no, if i dont want to mirror all i am : striping... or if i do the way i was planning... using 2 gig drives, : and only _use_ the space of one disk i'm mirroring to... I'm really quite interested in how you propose to have a mirrored system where drives can run at different steeds. Mirror works like this DATA ----> (going to disk) -------+--(and another copy)----+ | | disk 1 disk 2 So if i send some data to the (mirrored) disk, and disk1 is significantly faster than disk2, then disk1 will finish the write first.... so then do i just let it write more? Can you see a problem with this? What happens when disk1 is miles ahead.. who is supposed to keep track of all this data thats queued up for disk2? The OS? And if the disk 1 suddenly fails then you're screwed, and you fault tolerant system wan't very. : original question was, can i do it with freebsd? : seems to me answer is no. The reason FreeBSD can't do it is because the only people capable of writting it know that its not really the best idea. Peter -- Peter Childs --- http://www.imforei.apana.org.au/~pjchilds Finger pjchilds@al.imforei.apana.org.au for public PGP key Drag me, drop me, treat me like an object!