From owner-freebsd-geom@FreeBSD.ORG Thu Feb 10 12:44:44 2005 Return-Path: Delivered-To: freebsd-geom@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id E044F16A4CE for ; Thu, 10 Feb 2005 12:44:44 +0000 (GMT) Received: from darkness.comp.waw.pl (darkness.comp.waw.pl [195.117.238.136]) by mx1.FreeBSD.org (Postfix) with ESMTP id 306BC43D45 for ; Thu, 10 Feb 2005 12:44:44 +0000 (GMT) (envelope-from pjd@darkness.comp.waw.pl) Received: by darkness.comp.waw.pl (Postfix, from userid 1009) id A61A2AEA62; Thu, 10 Feb 2005 13:44:34 +0100 (CET) Date: Thu, 10 Feb 2005 13:44:34 +0100 From: Pawel Jakub Dawidek To: "Loren M. Lang" Message-ID: <20050210124434.GB1400@darkness.comp.waw.pl> References: <20050210023919.GC29396@alzatex.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="wzJLGUyc3ArbnUjN" Content-Disposition: inline In-Reply-To: <20050210023919.GC29396@alzatex.com> User-Agent: Mutt/1.4.2i X-PGP-Key-URL: http://people.freebsd.org/~pjd/pjd.asc X-OS: FreeBSD 5.2.1-RC2 i386 cc: freebsd-geom@freebsd.org Subject: Re: Does geom_uzip act as a variable size storage device? X-BeenThere: freebsd-geom@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: GEOM-specific discussions and implementations List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 10 Feb 2005 12:44:45 -0000 --wzJLGUyc3ArbnUjN Content-Type: text/plain; charset=iso-8859-2 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed, Feb 09, 2005 at 06:39:19PM -0800, Loren M. Lang wrote: +> How does the uzip geom work as a block device for a file system. My +> understanding of it is that it operates like a block device that trys to +> compress all data written to it using the same algorithm as used by +> pkzip and gzip. The problem I see with that is that not all data +> compresses by the same amount, some compresses more and other less, so a +> disk that acts as a compressor can hold different amounts of data +> depending on what's written to it. Filesystems like msdos and ufs2 +> don't support running on block devices of variable sizes as far as I know +> so how can I possibly format a uzip disk with a regular filesystem. I +> know that ufs supports being resized, but that's not the same as a block +> device that appears to be constantly changing size as data is being +> written to it so how does uzip work? Does it appear as some fixed size +> that may have wasted space if the data was able to compress really well, +> and when the data doesn't compress well enough, well, I don't know what +> would happen then. +>=20 +> Am I just missing something here or can the uzip geom be dangerous +> depending on how it's used and what fs it's formatted as. You cannot write to geom_uzip's providers. So you need to create provider image (compress your file system) and geom_uzip exports it as read-only provider. --=20 Pawel Jakub Dawidek http://www.wheel.pl pjd@FreeBSD.org http://www.FreeBSD.org FreeBSD committer Am I Evil? Yes, I Am! --wzJLGUyc3ArbnUjN Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (FreeBSD) iD8DBQFCC1cyForvXbEpPzQRAurQAKDB1dGRAEi4W72TSi3vhcXtIQtGsQCfReZG f0waQgIhqt7G4TmXJzFbdU4= =ORpp -----END PGP SIGNATURE----- --wzJLGUyc3ArbnUjN--