Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764697AbYHHWLj (ORCPT ); Fri, 8 Aug 2008 18:11:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1762130AbYHHVzg (ORCPT ); Fri, 8 Aug 2008 17:55:36 -0400 Received: from one.firstfloor.org ([213.235.205.2]:33747 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762367AbYHHVze (ORCPT ); Fri, 8 Aug 2008 17:55:34 -0400 Date: Fri, 8 Aug 2008 23:56:25 +0200 From: Andi Kleen To: Chris Mason Cc: Andi Kleen , Peter Zijlstra , linux-btrfs , linux-kernel , linux-fsdevel Subject: Re: Btrfs v0.16 released Message-ID: <20080808215625.GC9038@one.firstfloor.org> References: <1217962876.15342.33.camel@think.oraclecorp.com> <1218100464.8625.9.camel@twins> <1218105597.15342.189.camel@think.oraclecorp.com> <877ias66v4.fsf@basil.nowhere.org> <1218221293.15342.263.camel@think.oraclecorp.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1218221293.15342.263.camel@think.oraclecorp.com> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 644 Lines: 15 > So, the mirroring turns a single large write into two large writes. > Definitely not free, but always a fixed cost. Thanks for the explanation and the numbers. I see that's the advantage of copy-on-write that you can actually always cluster the metadata together and get always batched IO this way and then afford to do more of it. Still wondering what that will do to read seekiness. -Andi -- 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/