From owner-freebsd-fs Sat Sep 30 19:17:42 2000 Delivered-To: freebsd-fs@freebsd.org Received: from smtp04.primenet.com (smtp04.primenet.com [206.165.6.134]) by hub.freebsd.org (Postfix) with ESMTP id ECD9737B503 for ; Sat, 30 Sep 2000 19:17:39 -0700 (PDT) Received: (from daemon@localhost) by smtp04.primenet.com (8.9.3/8.9.3) id TAA22948; Sat, 30 Sep 2000 19:15:03 -0700 (MST) Received: from usr05.primenet.com(206.165.6.205) via SMTP by smtp04.primenet.com, id smtpdAAA4saiMS; Sat Sep 30 19:14:53 2000 Received: (from tlambert@localhost) by usr05.primenet.com (8.8.5/8.8.5) id TAA18354; Sat, 30 Sep 2000 19:17:22 -0700 (MST) From: Terry Lambert Message-Id: <200010010217.TAA18354@usr05.primenet.com> Subject: Re: Journaling Filesystems in bsd? (LFS, anyone?) To: karsten@rohrbach.de Date: Sun, 1 Oct 2000 02:17:17 +0000 (GMT) Cc: mbendiks@eunet.no (Marius Bendiksen), des@ofug.org (Dag-Erling Smorgrav), tuinstra@clarkson.edu (Dwight Tuinstra), freebsd-fs@FreeBSD.ORG (freebsd-fs) In-Reply-To: <20001001040520.D83678@rohrbach.de> from "Karsten W. Rohrbach" at Oct 01, 2000 04:05:20 AM X-Mailer: ELM [version 2.5 PL2] MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-fs@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Karsten writes: > Marius Bendiksen(mbendiks@eunet.no)@Mon, Sep 25, 2000 at 02:40:21PM +0200: > [...] > > more proper such filesystem. Or, get someone to port WAFL, and get NVRAM. > > this would be an interesting thing. with all the negative points of > nvram you got a few good points in wafl design which might be of > interest when it comes to lots of disks carrying one filesystem: > a) metadata is contained in files > b) those files are successors, referenced by the last on-volume snap > c) spreading the file system over a bunch of disks is easy, also without > lvm by design > d) devices in a bunch can be different size > e) you can hot-grow the filesystem (if your hardware supports hot-plug) > f) you can have as many files as you wish (or limit in your hashing > structure) on a volume > g) linear write window over all devices > > is netapp's wafl concept patented somehow? There are three patents of which I'm aware. That said, someone has already written a read-only WAFL FS for FreeBSD; it was announced to the FreeBSD FS list several weeks ago. Another interesting concept is described in: The Design and Implementation of a DCD Device Driver for UNIX Tycho Nightengale, Yiming Hu, Qing Yang 1999 Usenix Ignore the fact that Jordan and I are thanked for a tiny amount of information at the end of the paper: it's a very good paper, anyway. ;^) Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message