From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?utf-8?B?SsO2cm4=?= Engel Subject: Re: [RFC] TileFS - a proposal for scalable integrity checking Date: Sun, 29 Apr 2007 18:05:48 +0200 Message-ID: <20070429160547.GD30608@lazybastard.org> References: <20070428220522.GN11166@waste.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: Matt Mackall , linux-fsdevel@vger.kernel.org To: Andi Kleen Return-path: Received: from lazybastard.de ([212.112.238.170]:34461 "EHLO longford.lazybastard.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933327AbXD2QJw (ORCPT ); Sun, 29 Apr 2007 12:09:52 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org On Sun, 29 April 2007 18:34:59 +0200, Andi Kleen wrote: > Matt Mackall writes: >=20 > > This is a relatively simple scheme for making a filesystem with > > incremental online consistency checks of both data and metadata. > > Overhead can be well under 1% disk space and CPU overhead may also = be > > very small, while greatly improving filesystem integrity. >=20 > Problem I see is that your scheme doesn't support metadata checksums = only. Why? It is fairly simple to run many different schemes with this: - Generate checksums for everything, compare for each access. - Generate checksums for everything, only compare metadata checksums. - Generate checksums for everything, only compare at fsck time. - Generate metadata checksums, use 0x0000_0000 as data "checksums". - Not generate any checksums. Users without checksums would still pay the .1% space overhead, sure. I'd bet they already pay more for unused inodes. J=C3=B6rn --=20 ticks =3D jiffies; while (ticks =3D=3D jiffies); ticks =3D jiffies; -- /usr/src/linux/init/main.c - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel= " in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html