Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964916AbVKVLRa (ORCPT ); Tue, 22 Nov 2005 06:17:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964920AbVKVLRa (ORCPT ); Tue, 22 Nov 2005 06:17:30 -0500 Received: from mail.fh-wedel.de ([213.39.232.198]:17128 "EHLO moskovskaya.fh-wedel.de") by vger.kernel.org with ESMTP id S964916AbVKVLR3 (ORCPT ); Tue, 22 Nov 2005 06:17:29 -0500 Date: Tue, 22 Nov 2005 12:17:19 +0100 From: =?iso-8859-1?Q?J=F6rn?= Engel To: jdow Cc: Matthias Andree , linux-kernel@vger.kernel.org Subject: Re: what is our answer to ZFS? Message-ID: <20051122111719.GB14269@wohnheim.fh-wedel.de> References: <11b141710511210144h666d2edfi@mail.gmail.com> <20051121095915.83230.qmail@web36406.mail.mud.yahoo.com> <20051121101959.GB13927@wohnheim.fh-wedel.de> <20051121114654.GA25180@merlin.emma.line.org> <1132574831.15938.14.camel@localhost> <20051121131832.GB26068@merlin.emma.line.org> <008801c5eedc$f7277060$1225a8c0@kittycat> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <008801c5eedc$f7277060$1225a8c0@kittycat> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1160 Lines: 26 On Mon, 21 November 2005 12:48:44 -0800, jdow wrote: > > that was seldom if ever used by real people. I am not sure how I would > apply a checksum to each block of a file and still maintain reasonable > access speeds. It would be entertaining to see what the ZFS file system > does in this regard so that it doesn't slow down to essentially single > block per transaction disk reads or huge RAM buffer areas such as had > to be used with OFS. Design should be just as ZFS alledgedly does it. Store the checksum near the indirect block pointers. Seeks for checksums basically don't exist, as you need to seek for the indirect block pointers anyway. Only drawback is the effective growth of the area for the pointers+checksum blocks, which has a small impact on your caches. J?rn -- Courage is not the absence of fear, but rather the judgement that something else is more important than fear. -- Ambrose Redmoon - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/