From owner-freebsd-current@FreeBSD.ORG Thu May 20 13:08:34 2004 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 22D9E16A4CE for ; Thu, 20 May 2004 13:08:34 -0700 (PDT) Received: from main.gmane.org (main.gmane.org [80.91.224.249]) by mx1.FreeBSD.org (Postfix) with ESMTP id B4E3343D1D for ; Thu, 20 May 2004 13:08:33 -0700 (PDT) (envelope-from freebsd-current@m.gmane.org) Received: from list by main.gmane.org with local (Exim 3.35 #1 (Debian)) id 1BQtqD-00086D-00 for ; Thu, 20 May 2004 22:08:33 +0200 Received: from makrothumia.wingnet.net ([206.30.215.5]) by main.gmane.org with esmtp (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 20 May 2004 22:08:33 +0200 Received: from jesse by makrothumia.wingnet.net with local (Gmexim 0.1 (Debian)) id 1AlnuQ-0007hv-00 for ; Thu, 20 May 2004 22:08:33 +0200 X-Injected-Via-Gmane: http://gmane.org/ To: freebsd-current@freebsd.org From: Jesse Guardiani Date: Thu, 20 May 2004 16:08:29 -0400 Organization: WingNET Lines: 60 Message-ID: References: <35264.1085082037@critter.freebsd.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7Bit X-Complaints-To: usenet@sea.gmane.org X-Gmane-NNTP-Posting-Host: makrothumia.wingnet.net User-Agent: KNode/0.7.2 X-Mail-Copies-To: never Sender: news Subject: Re: GEOM portable filesystem abstraction? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: jesse@wingnet.net List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 20 May 2004 20:08:34 -0000 Poul-Henning Kamp wrote: > In message , Jesse Guardiani writes: >>Hello, >> >>I know next to nothing about GEOM, other than what >>the man page says (which I admittedly didn't read >>in full), so I'm probably totally off base, but I >>thought I'd ask this anyway: >> >>It seems like GEOM functions as a bit of a disk >>abstraction layer in FreeBSD. Would it be possible >>to port the GEOM subsystem as a loadable kernel >>module to Linux (and perhaps other OSes) to >>facilitate pluggable, portable filesystem code? > > Port it: yes. > > Portable filesystem code: no. > >>Perhaps if GEOM were ported to Linux then Linux >>could use FreeBSD's UFS2 code to read FreeBSD UFS >>filesystems? > > No, for that you need to port the UFS code from freebsd. > > GEOM operates at the sector level and does things like > mirror, stripe, RAID etc, but it sits under the filesystem > and doesn't know anything about files, directories etc. Hmmm... I don't know enough about how GEOM interacts with the kernel to brain storm further. Don't get me wrong, I'm not suggesting that anyone should write another abstraction layer and then port UFS to it and force everyone to use this slower version of the UFS filesystem by default. I'm simply suggesting that it might be useful (for things like portable devices or dual boot machines) to be capable of using a slightly slower filesystem that can be compiled as a loadable kernel module on multiple architectures and operating systems. I'd personally take the speed hit gladly if I *knew* that I could put a version of FreeBSD's GBDE encrypted filesystem on my 32gig 2.5" external USB 2.0/firewire hard disk and read/write it successfully under Windows, MacOSX, Linux, FreeBSD, etc... FAT32 does this already, but without the encryption, and without the reliability, scalability, speed, or durability of a real modern filesystem. I can't even really fsck FAT32 from FreeBSD, much less defrag it. -- Jesse Guardiani, Systems Administrator WingNET Internet Services, P.O. Box 2605 // Cleveland, TN 37320-2605 423-559-LINK (v) 423-559-5145 (f) http://www.wingnet.net