From owner-freebsd-hackers Fri Mar 3 13:43:46 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from gothic.iinet.net.au (gothic.iinet.net.au [203.59.24.252]) by hub.freebsd.org (Postfix) with ESMTP id 84E9237B6D8 for ; Fri, 3 Mar 2000 13:43:35 -0800 (PST) (envelope-from julian@elischer.org) Received: from jules.elischer.org (reggae-02-137.nv.iinet.net.au [203.59.91.137]) by gothic.iinet.net.au (8.8.5/8.8.5) with SMTP id FAA23704; Sat, 4 Mar 2000 05:43:08 +0800 Message-ID: <38C0312A.2781E494@elischer.org> Date: Fri, 03 Mar 2000 13:39:54 -0800 From: Julian Elischer X-Mailer: Mozilla 3.04Gold (X11; I; FreeBSD 4.0-CURRENT i386) MIME-Version: 1.0 To: David Scheidt Cc: Michael Bacarella , freebsd-hackers@FreeBSD.ORG Subject: Re: Copy-on-write filesystem References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG David Scheidt wrote: > > On Fri, 3 Mar 2000, Michael Bacarella wrote: > > > > > > > Upon reading of Microsoft's fabulous innovations in the filesystem arena, > > I started playing with some ideas of my own (not to be confused with > > ORIGINAL ideas) > > > > Can someone tell me why copy-on-write filesystems would be bad? > > It wouldn't be. This is how NetApp do their .snapshot direcotries. I think > they have some white papers on it on their website. It's very handy. Kirk McKusick is implementing a Copy-on write functionality for UFS. It is used in conjunction with Soft updates to produce snapshots. It's not what you asked for, but still relevant I think. One problem with "Copy-on-write, when applied to file copies is that you need to assign the blocks up front, even if you don't copy the data, as otherwise you could run out of space when the copy is actually needed. How many files would actually benefit from this? We already symlink and hardlink quite a few of them.. Julian > > David > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-hackers" in the body of the message -- __--_|\ Julian Elischer / \ julian@elischer.org ( OZ ) World tour 2000 ---> X_.---._/ presently in: Perth v To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message